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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 829 records · Page 46
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

Percutaneous CT-Guided Cryoablation as an Alternative Treatment for an Extensive Pelvic Bone Giant Cell Tumor

A giant cell tumor (GCT) is an intermediate grade, locally aggressive neoplasia. Despite advances in surgical and clinical treatments, cases located on the spine and pelvic bones remain a significant challenge. Failure of clinical treatment with denosumab and patient refusal of surgical procedures (hemipelvectomy) led to the use of cryoablation. We report the use of percutaneous CT-guided cryoablation as an alternative treatment, shown to be a minimally invasive, safe, and effective option for a GCT with extensive involvement of the pelvic bones and allowed structural and functional preservation of the involved bones.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2017

Combination of Surgical Drainage and Renal Artery Embolization: An Alternative Treatment for Xanthogranulomatous Pyelonephritis

Conventionally, xanthogranulomatous pyelonephritis is treated with antibiotics and drainage of abscess followed by nephrectomy for definitive treatment. Surgical excision of the affected kidney carries risk of significant complications. An alternative treatment modality is described in the form of embolization of the renal artery to devascularise the renal parenchyma and ablate the renal tissue, thus avoiding a major surgical procedure and the significant risks involved.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2017

Evaluation of Visualization Using a 50/50 (Contrast Media/Glucose 5% Solution) Technique for Radioembolization as an Alternative to a Standard Sandwich Technique

BackgroundRadioembolization (RE) with {sup 90}yttrium ({sup 90}Y) resin microspheres generally employs a sandwich technique with separate sequential administration of contrast medium (CM), followed by vehicle (e.g., glucose 5% [G5] solution), then {sup 90}Y resin microspheres (in G5), then G5, and then CM again to avoid contact of CM and microspheres under fluoroscopic guidance. This study evaluates the visualization quality and safety of a modified sandwich technique with a 50/50-mixture of CM (Imeron 300) and G5 for administration of {sup 90}Y resin microspheres.Materials and MethodsA retrospective analysis of 81 RE procedures in patients with primary or secondary liver tumors was performed. The quality of angiographic visualization of the hepatic vessels was assessed before the first injection and immediately before the whole dose has been injected. Visualization and flow rate were graded on a 5-point scale: 1 = very good to 5 = not visible/no antegrade flow. Univariate logistic regression models and multiple linear regression models were used to evaluate the prognostic variables associated with visualization and flow scores.ResultsVisualization quality was inversely related to flow rate, the lower the flow rate the better the grade of the visualization. Visualization quality was also inversely related to body-mass-index (BMI). Performing RE with the 50/50-CM/G5 mixture resulted in a mean injection time for 1 GBq of 15 min. No clinically significant adverse events, including radiation-induced liver disease were reported.ConclusionRE with a 50/50-mixture of CM and G5 for administration of {sup 90}Y resin microspheres in a modified sandwich technique is a safe administration alternative and provides good visualization of hepatic vessels, which is inversely dependent on flow rate and BMI. Injection time was reduced compared with our experience with the standard sandwich technique.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2018

A method of alternating characteristics with application to advection-dominated environmental systems

We present a numerical method for solving a class of systems of partial differential equations (PDEs) that arises in modeling environmental processes undergoing advection and biogeochemical reactions. The salient feature of these PDEs is that all partial derivatives appear in linear expressions. As a result, the system can be viewed as a set of ordinary differential equations (ODEs), albeit each one along a different characteristic. The method then consists of alternating between equations and integrating each one step-wise along its own characteristic, thus creating a customized grid on which solutions are computed. Since the solutions of such PDEs are generally smoother along their characteristics, the method offers the potential of using larger time steps while maintaining accuracy and reducing numerical dispersion. The advantages in efficiency and accuracy of the proposed method are demonstrated in two illustrative examples that simulate depth-resolved reactive transport and soil carbon cycling.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2011

Sulfuric acid-methanol electrolytes as an alternative to sulfuric-hydrofluoric acid mixtures for electropolishing of niobium

Attainment of the greatest possible interior surface smoothness is critical to meeting the performance demands placed upon niobium superconducting radiofrequency (SRF) accelerator cavities by next generation projects. Electropolishing with HF-H{sub 2}SO{sub 4} electrolytes yields cavities that meet SRF performance goals, but a less-hazardous, more environmentally-friendly process is desirable. Reported studies of EP on chemically-similar tantalum describe the use of sulfuric acid-methanol electrolytes as an HF-free alternative. Reported here are the results of experiments on niobium samples with this electrolyte. Voltammetry experiments indicate a current plateau whose voltage range expands with increasing acid concentration and decreasing temperature. Impedance spectroscopy indicates that a compact salt film is responsible for the current plateau. Equivalent findings in electropolishing chemically-similar tantalum with this electrolyte were interpreted due to as mass transfer limitation by diffusion of Ta ions away from the anode surface. We infer that a similar mechanism is at work here. Conditions were found that yield leveling and brightening comparable to that obtained with HF-H{sub 2}SO{sub 4} mixtures.

36 MATERIALS SCIENCE↗
DOE OSTI2017

Application of Multivariate Curve Resolution–Alternate Least Square Technique on Extracting Pure Spectral Components from Multiple Emitting Systems: a Case Study

Multiple emitting components in a fluorophoric system often produce complicated emission spectra. Extracting the individual spectral information from the composite spectra is important in order to comprehend the photophysical processes occurring in the multifluorophoric systems. Although the combination of Principal Component Analysis and Multivariate Curve Resolution-Alternate Least Square (PCA/MCR-ALS) technique is a well-known approach for curve deconvolution, its applicability in the spectral deconvolution of vibronically and electronically mixed up emitting systems as well as systems merged up with multiple electronic bands without a priori knowledge of the individual emitting species, is not properly studied. The present work highlights the strength of PCA/MCR-ALS in retrieving pure spectral information from the set of complex spectra arising out of the regular variation of causative factors that result in the variation of spectral composition. The retrieval of the emission bands utilizing the PCA/MCR-ALS technique has been made without having a priori information of the emitting species present in the multifluorophoric systems and the resolved spectra correspond well with the fluorescence spectra of the individual chemical species. The common curve fitting methods such as Gaussian and Lorentzian techniques have been found to be unsuccessful in providing meaningful photophysical information through the retrieved spectra. A comparative study of the curve fitting techniques MCR-ALS, Gaussian and Lorentzian in a set of complicated emission spectra of (i) pyrene and its excimer, (ii) pyrene and its excimer in presence of benzo[a]pyrene, and (iii) fisetin in bile salt medium is presented herein in details.

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2017

Two-Step Procedure of Fly Ash Modification as an Alternative Method for Creation of Functional Composite

An appropriate filler is a key component required to achieve an useful composite with expected properties. Not only sophisticated types of filler, like graphene are popular, but also more common ones, like silica flour or fly ash because of their low costs. Besides production costs, adequate size and possibility of functionalization of particles surface to create stable bonds with a matrix are essential in filler selection. To create an useful filler for epoxy resin based composites with use of a waste material, namely fly ash, two-step procedure was proposed. In the first part, raw material was sieved and five different ranges of the filler size were obtained. After mechanical tests with fracture toughness, tensile strength and Young Modulus, as well thermal conductivity, the best size of the fly ash was chosen for further modification. During the second step, filler was modified with coupling agent [3-(2-aminoethylamino)propyl]trimethoxysilane in order to enhance the coupling between particular components of composite. Presence of the silane layer was confirmed with infrared spectroscopy and scanning electron microscopy measurements, whilst prepared epoxy composite filled with silanized fly ash was examined similarly as previous composites. Obtained results have proved the significant influence of size of a filler and bonding to the matrix on mechanical and thermal properties of fly ash-epoxy resin composite. Proposed simple method of fly ash modification is an environmentally friendly way for utilization of the fly ash. Moreover, it creates an alternative material applicable in electrical devices as functional composite.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Physical Characterization of Bacterial Cellulose Produced by Komagataeibacter medellinensis Using Food Supply Chain Waste and Agricultural By-Products as Alternative Low-Cost Feedstocks

Bacterial cellulose (BC), which is a hemicellulose- and lignin-free type of cellulose with unique properties, was produced by Komagataeibacter medellinensis, a new acid-resistant bacterial strain, using not suitable human consumption and sub-valorized food supply chain waste (FSCW) and agricultural by-products, namely, rotten banana, rotten mango and cheese whey. The BC was analyzed using Fourier transform infrared (ATR-FTIR) , tensile test, atomic absorption spectroscopy and thermogravimetric analysis. The properties of the BC obtained from each culture medium used were different, ranging from a material with high resistance and stiffness (280.6 MPa, 9.4 GPa) to a material with low resistance and less stiffness (17.7 MPa, 0.8 GPa). These properties provide considerable opportunities for obtaining different materials with multiple applications, such as composite reinforcements, wound dressings and edible films. The highest production of BC was achieved with rotten banana medium, and this BC also had the highest tensile properties. Meanwhile, the BC produced from cheese whey medium had the highest maximum rate of degradation temperature at 368 °C. This research demonstrated that FSCW and agrowaste by-products are advantageous alternative feedstocks in terms of economics and environmental concerns for producing BC with multiple properties and fields of application.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Fiber from DDGS and Corn Grain as Alternative Fillers in Polymer Composites with High Density Polyethylene from Bio-based and Petroleum Sources

The steady increase in production of corn based ethanol fuel has dramatically increased the supply of its major co-product known as distiller’s dried grain with solubles (DDGS). Large amount of DDGS and corn flour are used as an animal feed. The elusieve process can separate DDGS or corn flour into two fractions: DDGS fraction with enhanced protein and oil content or corn flour fraction with high starch content, and hull fiber. This study investigated the feasibility of using fiber from DDGS and corn grain as alternative fillers to wood fiber in high density polyethylene (HDPE) composites made with two different sources of polymers. Two fiber loading rates of 30 and 50% were evaluated for fiber from DDGS, corn, and oak wood (control) to assess changes in various physical and mechanical properties of the composite materials. Two HDPE polymers, a bio-based HDPE made from sugarcane (Braskem), and a petroleum based HDPE (Marlex) were also compared as substrates. The biobased polymer composites with DDGS and corn fibers showed significantly lower water absorption than the Marlex composite samples. The Braskem composite with 30% DDGS fiber loading showed the highest impact resistance (80 J/m) among all the samples. The flexural properties showed no significant difference between the two HDPE composites.

36 MATERIALS SCIENCE↗
DOE OSTI2019

The Blocking Temperature of an Amorphous Alternate A and B Layers Cylindrical Nanowire

The blocking temperature of an amorphous cylindrical nanowire of length L and radius R is studied within the framework of Monte Carlo simulation based on Metropolis algorithm. The nanowire is formed by alternate layers of atoms A and B. The interlayer coupling J{sub AB} is ferromagnetic. The effects of the exchange couplings J{sub B} and J{sub AB}, the plane anisotropy D{sub xy}, and the amorphization α on the blocking temperature of the system are investigated. We found that the blocking temperature increases with increasing the value of the exchange couplings J{sub B} and J{sub AB} and decreases with increasing the plane anisotropy D{sub xy} and the degree of the amorphization α.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2018

Alternating Sums of Elements of Continued Fractions and the Minkowski Question Mark Function

The paper considers the function A(t) (0 ≤ t ≤ 1), related to the distribution of alternating sums of elements of continued fractions. The function A(t) possesses many properties similar to those of the Minkowski function ?(t). In particular, A(t) is continuous, satisfies similar functional equations, and A′(t) = 0 almost everywhere with respect to the Lebesgue measure. However, unlike ?(t), the function A(t) is not monotonically increasing. Moreover, on any subinterval of [1, 0], it has a sharp extremum.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2016

Alternate method of source preparation for alpha spectrometry: No electrodeposition, no hydrofluoric acid

An alternate method of preparing actinide alpha counting sources was developed in place of electrodeposition or lanthanide fluoride micro-precipitation. The method uses lanthanide hydroxide micro-precipitation to avoid the use of hazardous hydrofluoric acid. Lastly, it provides a quicker, simpler, and safer way of preparing actinide alpha counting sources in routine, production-type laboratories that process many samples daily.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2018

An alternative separation procedure for 90 Sr age dating using DGA Resin

The likelihood of an attack by a terrorist organization using a radiological dispersal device (RDD) is much higher than that of an attack with an improvised nuclear device or true nuclear weapon, as much less technical expertise is required to build an RDD. Consequently, there has been an effort to develop methods for age-dating radiological sealed sources in recent years. One such procedure, described by Steeb et al., is used for determining the age of 90 Sr sources. That procedure utilized a rather expensive extraction chromatography resin and was based on an uncommon apparatus with limited sample capacity for the separation step. The procedure also left the Zr fraction contaminated with the radioactive 90 Y daughter nuclide. This work investigates using an alternative separation scheme that utilizes a less costly resin in a widely available column configuration and results in the isolation of 90 Sr's stable granddaughter, 90 Zr, without 90 Y contamination. This allows the zirconium quantification to be done with a mass spectrometer outside the radiological environment and increases the number of instruments capable of making the measurement, which could allow measurements to be made more quickly.

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗
DOE OSTI2026

Ozonolysis of selenium: an alternative oxidation method for radiochemical separations of arsenic and selenium

Many arsenic and selenium radiochemical separation methods use hydrogen peroxide (H 2 O 2 ) to oxidize selenite (Se(IV)) to selenate (Se(VI)), but this reaction is challenging to control and replicate. Here, this study introduces a simple ozonolysis apparatus with an in-line oxygen-ozone generator and impinger system for rapid selenium oxidation in aqueous samples as an alternative to H 2 O 2 . The system quickly converts Se(IV) to Se(VI), enabling successful separations of arsenic-73 and selenium-75 with high recoveries using ion-exchange chromatography (1-X8). Compared to traditional H 2 O2 treatment, ozone oxidation is a faster and more easily controlled method for selenium redox chemistry.

and nuclear chemistry↗
DOE OSTI2020

Laser-Induced Plasma as a Method for the Metallic Materials Hardness Estimation: An Alternative Approach

The application of an alternative laser-induced breakdown spectroscopy (LIBS) method based on transversely excited atmospheric (TEA) CO2 laser was investigated for the first time for estimating the hardness of metallic materials. The human eye-safe (TEA) CO2 laser, operating at 10.6 µm, was used for plasma generation. The LIBS spectra were recorded by employing a cost-effective CCD camera for the time-integrated and spatial resolved measurements. The cast iron and aluminum alloys samples with different hardness have been tested. The ratio between the magnesium ionic and neutral lines in LIBS spectra was applied for estimating the material hardness. In addition, the hardness of all samples included in this study was determined using the conventional method for material hardness determination, i.e. Vickers hardness test. The linear dependence of magnesium lines intensity ratio on the sample’s hardness was obtained for both kinds of materials. Profilometric measurements were used to verify that the newly-introduced method is almost nondestructive for the investigated metals. The results obtained in the present work confirmed the potential of using this original LIBS system not only for the fast elemental analysis but also for the direct estimation of the hardness of metals and alloys. © 2020, Springer Science+Business Media, LLC, part of Springer Nature.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Alternative trajectories of electron density to plot the atomic connectivity graph in the region of nondirectional interactions

Model supramolecular associates possessing nondirectional intermolecular interactions were investigated in order to demonstrate the opportunity of plotting of an atomic connectivity graph based on trajectories of Hessian eigenvector of electron density corresponding to the largest eigenvalue. Such trajectories are a reasonable alternative to the gradient bond paths in the case of proximity of the latter to the T-shaped form upon the presence of parallel surface of the zero-flux of electron density in the neighborhood of gradient-based trajectory.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2018

Long-Lived Plasma Formations in the Atmosphere as an Alternative Energy Source

A model of a stable plasma formation, based on radial quantum oscillations of charged particles, is discussed. The given plasmoid is described with the help of the nonlinear Schrödinger equation. A new phenomenon of effective attraction between oscillating charged particles is considered within the framework of the proposed model. The possible existence of a composite plasma structure is also discussed. Hypotheses about using the obtained results to describe natural long-lived plasma formations which can serve as alternative energy sources are advanced.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2020

An Alternative Casting Technique to Improve the Creep Resistance of Cast INCONEL Alloy 740H

The increasing performance requirements of power plant designs, such as advanced-ultra supercritical (A-USC), require the use of Ni-based superalloys to replace high-strength, ferritic-martensitic steels for components subjected to temperatures above 898 K (625 °C) and for austenitic stainless steels components at temperatures above 973 K (700 °C). To date, commercial Ni-based superalloy INCONEL 740H has been shown to be appropriate for use in A-USC power plants as boiler components in a wrought product. However, large complex components in boilers as well as other casings in the turbine and valve chest require castings of a thick-wall nature. Using the alloy in its cast form would be significantly valuable in terms of range of component size, geometry and complexity. Previous investigations revealed short creep lives from cast INCONEL alloy 740H. Here in this investigation, an alternative casting route that utilized a melt procedure resulting in a fine-grain casting, and in conjunction with a computationally optimized homogenization heat treatment, not only controlled the grain size and grain boundary structure but minimized chemistry variability and segregation. A primarily equiaxed and homogenous grain size distribution was obtained from this approach with better repartition of M 23 C 6 carbides along the grain boundaries. Furthermore, better than 38 pct increase was obtained for this material in comparison to the creep life obtained from the best performing conventionally cast material. More importantly, the fine-grain homogenized (FGH) casting route resulted in the Larson–Miller plot for this material that coincided with that of wrought alloy 740. At low creep stresses (with a test still in progress), the FGH casting is resulting in higher values of the LMP than the wrought alloy.

36 MATERIALS SCIENCE↗