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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 523 records · Page 29
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

HYBRID COMPOSITES VIA CO-EXTRUSION ADDITIVE MANUFACTURING-COMPRESSION MOLDING FOR PERFORMANCE OPTIMIZATION

The growing demand for hybrid polymer composites with multifunctional properties has led to the development of various hybridization techniques, such as multi-material compounding and controlled laminate stacking sequence. In this study, a novel hybrid manufacturing approach was used by integrating a multiplexing extrusion system (MExS) based on additive manufacturing with subsequent compression molding process. This technique enabled the co-extrusion of different materials during the additive manufacturing process to fabricate composites with tailored performance. The developed hybrid composite featured a skin layer of glass fiberreinforced polycarbonate (PC/GF) encapsulating a carbon fiber-reinforced acrylonitrile butadiene styrene (CF/ABS) core. The structure was engineered to promote improved thermal and impact resistance at the surface, supported by a stiff core for enhanced overall mechanical integrity. Mechanical, thermal and morphological properties of the hybrid composites were investigated to understand trade-offs in performance compared to a single-material system. The results demonstrate that this approach enables the production of multifunctional composites suitable for applications such as automotive body panels and protective housings, where a balance of weight, mechanical strength, and thermal performance is essential.

Wasti, Sanjita [ORNL]↗
DOE OSTI2025

Do Piperonyl Butoxide Long-Lasting Insecticide Treated Nets Provide Additional Protection Against Malaria Infections Compared with Conventional Nets in an Operational Setting in Western Kenya?

Malaria control in sub-Saharan Africa has stagnated despite widespread adoption of control measures such as long-lasting insecticidal nets (LLINs). Progress has stalled, in part, because of pyrethroid insecticide resistance, driving the need for retooling to increase the effectiveness of bed nets. Consequently, LLINs have been treated with the chemical synergist piperonyl butoxide (PBO). Piperonyl butoxide LLINs have been shown to be efficacious in controlled settings; however, their effectiveness in real-world settings warrants investigation. In Bungoma County, Western Kenya, a cohort of 768 participants was followed from June 2017 to December 2023 via active and passive surveillance. Household visits were conducted monthly, during which LLIN use for nets distributed in 2017 and 2021 was recorded, and symptomatic malaria cases were identified using rapid diagnostic tests (RDTs). The comparative effectiveness of PBO versus conventional LLINs was assessed in terms of malaria infections. A multilevel logistic regression model was fit with monthly RDT results as the dependent variable. The study results indicate that PBO LLINs provide greater protection against malaria at the individual level than conventional LLINs (odds ratio: 0.70; 95% CI: 0.47–1.03), although the findings were not statistically significant. The added protection against malaria infections provided by PBO LLINs compared with conventional LLINs observed in the current study aligns with findings from most previous studies, although this finding was not statistically significant. In areas with documented pyrethroid resistance, the use of LLINs with an added synergist, such as PBO, can provide additional protection against malaria infections (compared with pyrethroid-only LLINs) and should be considered for scaled-up scenarios despite the additional cost.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2026

AMVOS: Additive Manufacturing Video Object Segmentation Dataset

This dataset provides labeled video frames from four additive manufacturing (AM) processes for video object segmentation (VOS) tasks. It contains 90 video segments comprising 900 individually annotated frames across five AM datasets: laser hot-wire directed energy deposition (LHW-DED), tungsten inert gas wire arc additive manufacturing (TIG-WAAM), plasma arc welding (PAW), visible-light polymer extrusion (visPolymer), and near-infrared polymer extrusion (irPolymer). Each video segment consists of 10 contiguous frames with corresponding pixel-level object instance annotations. Depending on the process, two of four object classes are labeled per frame: Melt Pool, Feed Wire, Nozzle, or Material. Raw frames are provided as .jpg files and annotations as palettized .png files. The dataset follows the directory structure of established VOS benchmarks (DAVIS, YouTube-VOS, MOSE), enabling direct integration into VOS model training and evaluation pipelines for foundation model fine-tuning, domain adaptation, or zero-shot performance benchmarking. Data was collected at Oak Ridge National Laboratory's Manufacturing Demonstration Facility.

Wetzel, Jon [ORNL]↗
NASA NTRS1971

Heat addition to a subsonic boundary layer: A preliminary analytical study

A preliminary analytical study of the effects of heat addition to the subsonic boundary layer flow over a typical airfoil shape is presented. This phenomenon becomes of interest in the space shuttle mission since heat absorbed by the wing structure during re-entry will be rejected to the boundary layer during the subsequent low speed maneuvering and landing phase. A survey of existing literature and analytical solutions for both laminar and turbulent flow indicate that a heated surface generally destabilizes the boundary layer. Specifically, the boundary layer thickness is increased, the skin friction at the surface is decreased and the point of flow separation is moved forward. In addition, limited analytical results predict that the angle of attack at which a heated airfoil will stall is significantly less than the stall angle of an unheated wing. These effects could adversely affect the lift and drag, and thus the maneuvering capabilities of booster and orbiter shuttle vehicles.

Macha, J. M.↗
NASA NTRS1972

Addition-type polyimides from solutions of monomeric reactants

The monomeric reactants approach was used to fabricate addition-type polyimide/graphite fiber composites with improved mechanical properties and thermal stability characteristics over those of composites derived from addition-type amide acid prepolymers. A screening study of 24 different monomer combinations was performed. The results of a more extensive investigation of a selected number of monomer combinations showed that the combination providing the best thermomechanical properties was 5-norbornene-2.3-dicarboxylic acid monomethyl ester/4,4(')-methylenedianiline/3,3(')4,4(')-benzophenonetetracarboxylic acid dimethyl ester at a molar ratio of 2/3.09/2.09.

Delvigs, P.↗
NASA NTRS1972

Addition-type polyimides from solutions of monomeric reactants

The monomeric reactants approach was used to fabricate addition-type polyimide/graphite fiber composites with improved mechanical properties and thermal stability characteristics over those of composites derived from addition-type amide acid prepolymers. A screening study of 24 different monomer combinations was performed. The results of a more extensive investigation of a selected number of monomer combinations showed that the combination providing the best thermomechanical properties was 5-norbornene-2,3-dicarboxylic acid monomethyl ester/4,4'-methylenedianiline/3,3'4,4'-benzophenone tetracarboxylic acid dimethyl ester at a molar ratio of 2/3.09/2.09.

Delvigs, P.↗
NASA NTRS1971

The effect of solute additions on the steady-state creep behavior of dispersion-strengthened aluminum.

The effect of solute additions on the steady-state creep behavior of coarse-grained dispersion-strengthened aluminum alloys was studied. Recrystallized dispersion-strengthened solid solutions were found to have stress and temperature sensitivities quite unlike those observed in single-phase solid solutions having the same composition and grain size. The addition of magnesium or copper to the matrix of a recrystallized dispersion-strengthened aluminum causes a decrease in the steady-state creep rate which is much smaller than that caused by similar amounts of solute in single-phase solid solutions. All alloys exhibited essentially a 4.0 power stress exponent in agreement with the model of Ansell and Weertman. The activation energy for steady-state creep in dispersion-strengthened Al-Mg alloys, as well as the stress dependence, was in agreement with the physical model of dislocation climb over the dispersed particles.

Reynolds, G. H.↗
NASA NTRS1972

Addition-type polyimides from solutions of monomeric reactants.

The monomeric reactants approach was used to fabricate addition-type polyimide/graphite fiber composites with improved mechanical properties and thermal stability characteristics over those of composites derived from addition-type amide acid prepolymers. A screening study of 24 different monomer combinations was performed. The results of a more extensive investigation of a selected number of monomer combinations showed that the combination providing the best thermomechanical properties was 5-norbornene-2,3-dicarboxylic acid monomethyl ester/4,4'-methylenedianiline/3,3'4,4'-benzophenonetetracarboxylic acid dimethyl ester at a molar ratio of 2/3.09/2.09.

Delvigs, P.↗
NASA NTRS1974

Effect of primary-zone equivalence ratio and hydrogen addition on exhaust emission in a hydrocarbon-fueled combustor

The effects of reducing the primary-zone equivalence ratio on the exhaust emission levels of oxides of nitrogen, carbon monoxide, and unburned hydrocarbons in experimental hydrocarbon-fueled combustor segments at simulated supersonic cruise and idle conditions were investigated. In addition, the effects of the injection of hydrogen fuel (up to 4 percent of the total weight of fuel) on the stability of the hydrocarbon flame and exhaust emissions were studied and compared with results obtained without hydrogen addition.

Norgren, C. T.↗
NASA NTRS1975

Effects of silicon additions on oxidation and mechanical behavior of the nickel-base superalloy B-1900

Test specimens with nominal additions of Si were tested in oxidation, thermal fatigue, sulfidation, tension, and stress rupture, and were also extensively studied metallographically. Alloy B-1900 modified with 0.6- or 1.2-wt% Si exhibited oxidation resistance equivalent to that of aluminide-coated B-1900 during cyclic, high-gas-velocity oxidation tests. Resistances to thermal fatigue and sulfidation were improved by the Si additions, but were not superior to aluminide-coated B-1900. Stress-rupture tests at 1000 C of specimens given the standard heat treatment to simulate an aluminide coating cycle showed Si to be detrimental. However, application of another heat treatment increased the rupture life of the alloy with 0.6-wt% Si to that of the unmodified B-1900 given the standard heat treatment.

Miner, R. V., Jr.↗
NASA NTRS1975

Theoretical effect of modifications to the upper surface of two NACA airfoils using smooth polynomial additional thickness distributions which emphasize leading edge profile and which vary linearly at the trailing edge

An investigation was conducted on a CDC 7600 digital computer to determine the effects of additional thickness distributions to the upper surface of airfoils. The additional thickness distribution had the form of a continuous mathematical function which disappears at both the leading edge and the trailing edge. Results were obtained at a Mach number of 0.2 with an angle of attack of 6 deg. All calculations employed the full potential flow equations for two dimensional flow. The relaxation method of Jameson was used for solution of the potential flow equations. It is shown that increasing the thickness and variations in shape increases the lift and the adverse pitching moment coefficients.

Hague, D. S.↗
NASA NTRS1977

Consolidation of silicon nitride without additives

The feasibility of producing a sound, dense Si3N4 body without additives was explored, using conventional gas hot isostatic pressing techniques and an uncommon hydraulic hot isostatic pressing technique. These two techniques produce much higher pressure 275-413 MN/m sq (40,000 - 60,000 psi) than hot-pressing techniques. Evaluation was based on density measurement, microscopic examination, both optical and electron, and X-ray diffraction analysis. The results are summarized as follows: (1) Si3N4 can be densified to high density, greater than 95% of theoretical, without additions. (2) The higher density Si3N4 specimens appear to be associated with a greater amount of alpha to beta transformation. (3) Under high pressure, the alpha to beta transformation can occur at a temperature as low as 1150 C. (4) Grain deformation and subsequent recrystallization and grain refinement result from hot isostatic pressing of Si3N4.

Sikora, P. F.↗
NASA NTRS1977

Effects of Fe2O3 addition on the nitridation of silicon powder

The reaction of silicon powder and nitrogen was studied in the range of 1300-1400 C. When an addition of Fe2O3 was more than 0.8wt%, the reaction was linear and compared to samples with no Fe2O3, the reaction velocity increased 5 to 10 times. The reactions were mediated by the process of peeling and cracking in a thin layer of Si2N4 formed on the silicon particles or on the surface of the Fe-Si melts. As the addition of Fe2O3 increased, the reaction activation energy for highly pure samples decreased. Fe2O3 which exceeded the Si3N4 solubility limits was finally converted to d-Fe.

Hasegawa, Y.↗
NASA NTRS1978

The effect of minor additions of titanium on the fracture toughness of Fe-12Ni alloys at 77K

Titanium additions ranging from 0.18 to 0.99 atomic percent and heat treatments of 2 hours at 550, 685 and 820 C respectively followed by a water quench were considered. Cubic and rectangular shaped inclusions were noted in the SEM fractographs of the alloys with the Ti additions. A fine precipitate was observed by TEM for the Fe-12Ni-0.18Ti alloys heat treated at 550 C; this precipitate was not observed for the 685 and 820 C heat treatments of the same alloy. Auger mappings of the fracture surfaces indicated a weak to moderate association of the interstitials C, N and O with Ti, the degree of which depended on the particular interstitial and the heat treatment temperature.

Conrad, H.↗
NASA NTRS1978

Inhibition of hot salt corrosion by metallic additives

The effectiveness of several potential fuel additives in reducing the effects of sodium sulfate-induced hot corrosion was evaluated in a cyclic Mach 0.3 burner rig. The potential inhibitors examined were salts of Al, Si, Cr, Fe, Zn, Mg, Ca, and Ba. The alloys tested were IN-100, U-700, IN-738, IN-792, Mar M-509, and 304 stainless steel. Each alloy was exposed for 100 cycles of 1 hour each at 900 C in combustion gases doped with the corrodant and inhibitor salts and the extent of attack was determined by measuring maximum metal thickness loss. The most effective and consistent inhibitor additive was Ba (NO3)2 which reduced the hot corrosion attack to nearly that of simple oxidation.

Deadmore, D. L.↗
NASA NTRS1976

Consolidation of silicon nitride without additives

The use of ceramics for gas turbine engine construction might make it possible to increase engine efficiency by raising operational temperatures to values beyond those which can be tolerated by metallic alloys. The most promising ceramics being investigated in this connection are Si3N4 and SiC. A description is presented of a study which had the objective to produce dense Si3N4. The two most common methods of consolidating Si3N4 currently being used include hot pressing and reaction sintering. The feasibility was explored of producing a sound, dense Si3N4 body without additives by means of conventional gas hot isostatic pressing techniques and an uncommon hydraulic hot isostatic pressing technique. It was found that Si3N4 can be densified without additions to a density which exceeds 95% of the theoretical value

Sikora, P. F.↗
NASA NTRS1978

Effect of gaseous additives on the response of the helium ionization detector

Changes in the response of the helium ionization detector which occur when varying amounts of gases are added to the helium carrier gas at different applied voltages have been investigated. The addition of hydrogen, argon, oxygen, or nitrogen to the helium carrier gas causes an increase in the detector response when the voltage applied to the detector is more than 350 V, and a decrease in the detector response when the applied voltage is less than 350 V. It was also found that the detector responds positively and linearly to neon when high concentrations of gaseous additives were added to the helium.

Andrawes, F. F.↗
NASA NTRS1980

Additive improves engine-oil performance

Tests of metal erosion in operating engines show that addition of 5% tricresyl phosphate significantly reduces wear rate. Commercial 10W30 oil gives one tenth wear and degrades less with additive.

Babecki, A. J.↗