Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Routing”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,585 records · Page 88
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

Chemical Attribution of Fentanyl Using Multivariate Statistical Analysis of Orthogonal Mass Spectral Data

Attribution of the origin of an illicit drug relies on identification of compounds indicative of its clandestine production and is a key component of many modern forensic investigations. Here, the results of these studies can yield detailed information on method of manufacture, starting material source, and final product, all critical forensic evidence. In the present work, chemical attribution signatures (CAS) associated with the synthesis of the analgesic fentanyl, N-(1-phenylethylpiperidin-4-yl)-N-phenylpropanamide, were investigated. Six synthesis methods, all previously published fentanyl synthetic routes or hybrid versions thereof, were studied in an effort to identify and classify route-specific signatures. A total of 160 distinct compounds and inorganic species were identified using gas and liquid chromatographies combined with mass spectrometric methods (gas chromatography/mass spectrometry (GC/MS) and liquid chromatography–tandem mass spectrometry-time of-flight (LC–MS/MS-TOF)) in conjunction with inductively coupled plasma mass spectrometry (ICPMS). The complexity of the resultant data matrix urged the use of multivariate statistical analysis. Using partial least-squares-discriminant analysis (PLS-DA), 87 route-specific CAS were classified and a statistical model capable of predicting the method of fentanyl synthesis was validated and tested against CAS profiles from crude fentanyl products deposited and later extracted from two operationally relevant surfaces: stainless steel and vinyl tile. Finally, this work provides the most detailed fentanyl CAS investigation to date by using orthogonal mass spectral data to identify CAS of forensic significance for illicit drug detection, profiling, and attribution.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Multimodal MSI in Conjunction with Broad Coverage Spatially Resolved MS2 Increases Confidence in Both Molecular Identification and Localization

One critical aspect of mass spectrometry imaging (MSI) is the need to con?dently identify detected analytes. While orthogonal tandem MS (e.g., LC-MS2) experiments from sample extracts can assist in annotating ions, the spatial information about these molecules is lost. Accordingly, this could cause mislead conclusions, especially in cases where isobaric species exhibit di?erent distributions within a sample. In this Technical Note, we employed a multimodal imaging approach, using matrix assisted laser desorption/ionization (MALDI)-MSI and liquid extraction surface analysis (LESA)-MS2I, to con?dently annotate and One critical aspect of mass spectrometry imaging (MSI) is the need to con?dently identify detected analytes. While orthogonal tandem MS (e.g., LC-MS2) experiments from sample extracts can assist in annotating ions, the spatial information about these molecules is lost. Accordingly, this could cause mislead conclusions, especially in cases where isobaric species exhibit di?erent distributions within a sample. In this Technical Note, we employed a multimodal imaging approach, using matrix assisted laser desorption/ionization (MALDI)-MSI and liquid extraction surface analysis (LESA)-MS2I, to con?dently annotate and localize a broad range of metabolites involved in a tripartite symbiosis system of moss, cyanobacteria, and fungus. We found that the combination of these two imaging modalities generated very congruent ion images, providing the link between highly accurate structural information onfered by LESA and high spatial resolution attainable by MALDI. These results demonstrate how this combined methodology could be very useful in di?erentiating metabolite routes in complex systems.

Velickovic, Dusan↗
DOE OSTI2015

Deformation Twinning of a Silver Nanocrystal under High Pressure

Within a high-pressure environment, crystal deformation is controlled by complex processes such as dislocation motion, twinning, and phase transitions, which change materials' microscopic morphology and alter their properties. Understanding a crystal's response to external stress provides a unique opportunity for rational tailoring of its functionalities. It is very challenging to track the strain evolution and physical deformation from a single nanoscale crystal under high-pressure stress. Here, we report an in situ three-dimensional mapping of morphology and strain evolutions in a single-crystal silver nanocube within a high-pressure environment using the Bragg Coherent Diffractive Imaging (CDI) method. We observed a continuous lattice distortion, followed by a deformation twining process at a constant pressure. The ability to visualize stress-introduced deformation of nanocrystals with high spatial resolution and prominent strain sensitivity provides an important route for interpreting and engineering novel properties of nanomaterials.

coherent diffractive imaging↗
DOE OSTI2025

Demonstration of MgCr 2– x Mn x O 4 Spinel Oxide Cathodes in High-Voltage Mg Batteries

Solid-solution oxide spinels with high redox voltages and facile Mg 2+ mobility have been identified as promising candidates for practical, high-voltage cathodes in Mg batteries. In this work, we discuss the development of MgCr 2-x Mn x O 4 [x = 0.5, 1, 1.2] solid-solution spinel oxides as a cathode material and their electrochemical performance paired with an Mg anode in a full cell. This work presents the first demonstration of full cells with these materials. Mg-Cr-Mn spinel oxides with varying Cr and Mn contents were synthesized using alternative synthetic routes for optimal electrochemical performance. High-resolution synchrotron powder X-ray diffraction (PXRD), solid-state nuclear magnetic resonance (NMR) spectroscopy, and electron microscopy showed that these different synthetic routes resulted in changes in structures and particle morphologies, which in turn affect the electrochemical performance. Particularly, the urea coprecipitation synthetic route resulted in high-surface-area particles that enabled lower overpotentials and increased discharge capacity. The high surface area also resulted in expedited structural degradation caused by the irreversible migration of Mg 2+ into normally vacant 16c sites in the spinel lattice. This structural degradation was lessened by using a hydrosauna-urea synthesis method, which decreased the Mg/Mn inversion ratio while retaining high-surface-area particles with good cycling performance. Furthermore, our findings highlight the necessity for high surface area or nanostructured spinel oxide cathodes with minimized Mg-Mn inversion to enable spinel oxide cathodes in Mg full cells.

Mg anode↗
DOE OSTI2016

Graphene Nanocomposites with High Molecular Weight Poly(ε-caprolactone) Grafts: Controlled Synthesis and Accelerated Crystallization

Grafting of high molecular weight polymers to graphitic nanoplatelets is a critical step toward the development of high performance graphene nanocomposites. However, designing such a grafting route has remained a major impediment. Herein, we report a "grafting to" synthetic pathway by which high molecular weight polymer, poly(e-caprolactone) (PCL), is tethered, at high grafting density, to highly anisotropic graphitic nanoplatelets. The efficacy of this tethering route and the resultant structural arrangements within the composite are confirmed by neutron and X-ray scattering measurements in the melt and solution phase. In the semicrystalline state, Xray analysis indicates that chain tethering onto the graphitic nanoplatelets results in conformational changes of the polymer chains, which enhance the nucleation process and aid formation of PCL crystallites. This is corroborated by the superior thermal properties of the composite, manifested in accelerated crystallization kinetics and a significant increase in the thermal degradation temperature. Lastly, in principle, this synthesis route can be extended to a variety of high molecular weight polymers, which can open new avenues to solution-based processing of graphitic nanomaterials and the fabrication of complex 3D patterned graphitic nanocomposites.

36 MATERIALS SCIENCE↗
DOE OSTI2016

Self-Assembled, Nanostructured, Tunable Metamaterials via Spinodal Decomposition

Self-assembly via nanoscale phase separation offers an elegant route to fabricate nanocomposites with physical properties unattainable in single-component systems. One important class of nanocomposites are optical metamaterials which exhibit exotic properties and lead to opportunities for agile control of light propagation. Such metamaterials are typically fabricated via expensive and hard-to-scale top-down processes requiring precise integration of dissimilar materials. In turn, there is a need for alternative, more efficient routes to fabricate large-scale metamaterials for practical applications with deep-subwave length resolution. Here, we demonstrate a bottom-up approach to fabricate scalable nanostructured metamaterials via spinodal decomposition. To demonstrate the potential of such an approach, we leverage the innate spinodal decomposition of the VO 2 -TiO 2 system, the metal-to-insulator transition in VO 2 , and thin-film epitaxy, to produce self-organized nanostructures with coherent interfaces and a structural unit cell down to 15 nm (tunable between horizontally and vertically aligned lamellae) wherein the iso-frequency surface is temperature-tunable from elliptic to hyperbolic dispersion producing metamaterial behavior. These results provide an efficient route for the fabrication of nanostructured metamaterials and other nanocomposites for desired functionalities.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Techno-economic analysis and life-cycle analysis of two light-duty bio-blendstocks: isobutanol and aromatic rich hydrocarbons

Isobutanol and aromatic-rich hydrocarbons (ARHC) are two biomass-derived high octane blendstocks that could be blended with petroleum gasoline for use in optimized spark-ignition engines in light-duty vehicles, potentially increasing engine efficiency. To evaluate technology readiness, economic viability, and environmental impacts of these technologies, we use detailed techno-economic analysis (TEA) and life-cycle analysis (LCA). We assumed isobutanol is produced via biochemical conversion of an herbaceous feedstock blend while ARHC is produced via thermochemical conversion of a woody feedstock blend.The minimum estimated fuel selling price (MFSP) of isobutanol ranged from $5.57/gasoline gallon equivalent (GGE) based on today’s technology to $4.22/GGE with technology advancements. The MFSP of ARHC could decline from $5.20/GGE based on today’s technology to $4.20/GGE as technology improves. Both isobutanol and ARHC offer about 73% GHG emission reduction relative to petroleum gasoline per LCA of these two bio-blendstocks. On the other hand, water consumption in the production of both bio-blendstocks exceeds that of conventional gasoline although process engineering offers routes to cutting water consumption. Over their life cycles, both isobutanol and ARHC emit more NOx and PM2.5 than petroleum gasoline.Improving the energy efficiency and lowering air emissions from agricultural equipment will reduce the life-cycle air pollutant emissions of these bio-blendstocks.

techno-economic analysis, life-cycle analysis, bio↗
DOE OSTI2016

Exceptional Morphology-Preserving Evolution of Formamidinium Lead Triiodide Perovskite Thin Films via Organic-Cation Displacement

Here we demonstrate a radically different chemical route for the creation of HC(NH2)2PbI3 (FAPbI3) perovskite thin films. This approach entails a simple exposure of as-synthesized CH3NH3PbI3 (MAPbI3) perovskite thin films to HC(=NH)NH2 (formamidine or FA) gas at 150 degrees C, which leads to rapid displacement of the MA+ cations by FA+ cations in the perovskite structure. The resultant FAPbI3 perovskite thin films preserve the microstructural morphology of the original MAPbI3 thin films exceptionally well. Importantly, the myriad processing innovations that have led to the creation of high-quality MAPbI3 perovskite thin films are directly adaptable to FAPbI3 through this simple, rapid chemical-conversion route. Accordingly, we show that efficiencies of perovskite solar cells fabricated with FAPbI3 thin films created using this route can reach -18%.

14 SOLAR ENERGY↗
DOE OSTI2019

Streamflow in the Columbia River Basin: Quantifying Changes Over the Period 1951-2008 and Determining the Drivers of Those Changes

Trend, detection, and attribution analyses were performed using naturalized streamflow observations and routed land surface model runoff for 10 subbasins in the Columbia River Basin during water years 1951–2008. The Energy Exascale Earth System land-surface model (ELM) version 1.0 and the Routing Application for Parallel computatIon of Discharge (RAPID) routing model were used to conduct semi-factorial simulations driven by multiple sets of bias-corrected forcing data sets. Four main potential drivers, including climate change (CLMT), CO 2 concentration (CO 2 ), nitrogen deposition (NDEP), and land use and land cover change (LULCC), were analyzed during the assessment. All subbasins showed significant (α = 0.10) declines in the observed amount of annual total streamflow, except for the Middle and Upper Snake and Upper Columbia Subbasins. These declines were led by significant decreases in June–October streamflow, which also directly led to significant decreases in peak and summer streamflow. Except for the Snake River Subbasins, LULCC had the same pattern of declines in monthly streamflow, but the period was shifted to May–September. NDEP also had significant trends in June–October; however, rather than decreases, the trends showed significant increases in streamflow. While there were significant trends in CO 2 , NDEP, and LULCC, their signals of change were weak in comparison to the signal in CLMT and the natural internal variability found in streamflow. Overall, the detection and attribution analysis showed that the historical changes found in annual total, center of timing of, and summer mean streamflow could be attributed to changing climate and variability.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2021

Impact of Lateral Flow on Surface Water and Energy Budgets over the Southern Great Plains – A Modeling Study

As we see the horizontal grid spacing decrease, treatment of hydrologic processes in land surface models, such as the lateral flow of surface and subsurface flow, need to be explicitly represented. Unlike previous studies that mainly focused on the mountainous regions, in this study the offline WRF-Hydro model is employed to study the impact of lateral flow on soil moisture and energy fluxes over the relatively flat southern Great Plains (SGP). The vast amount of measurements over the SGP provide an unique opportunity to assess the model behavior. In addition, newly developed land surface properties and input forcing are ingested into the model, in an attempt to reduce uncertainties associated with the initial and boundary forcing and help to identify model deficiencies. Our results show that the more realistic inputs (parameters, soil types, forcing) lead to larger underestimation of latent heat flux and dry bias, indicating the existence of model structural uncertainty (embedded errors) in WRF-Hydro that need to be characterized to inform future model development efforts. Including lateral flow processes partly mitigates the model deficiencies in representing hydrologic processes and alleviates the dry bias. In particular, both surface and subsurface lateral flow increase soil moisture mainly over the lower elevations, except that subsurface flow also affects soil moisture over steeper terrains. Additional simulations are performed to assess the effect of routing resolution on model results. When LSM resolution is high, noticeable differences in soil moisture are produced between different routing resolutions especially over steep terrain. Whereas when LSM resolution is coarse, differences between routing resolutions become negligible, especially over flat terrain.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2018

Three-dimensional migration behavior of juvenile salmonids in reservoirs and near dams

To acquire 3-D tracking data on juvenile salmonids, Juvenile Salmon Acoustic Telemetry System (JSATS) cabled hydrophone arrays were deployed in the forebays of two dams on the Snake River and at a mid-reach reservoir between the dams. The depth distributions of fish were estimated by statistical analyses performed on large 3-D tracking data sets from ~33,500 individual acoustic tagged yearling and subyearling Chinook salmon and juvenile steelhead at the two dams in 2012 and subyearling Chinook salmon at the two dams and the mid-reach reservoir in 2013. This research investigated the correlation between vertical migration behavior and passage routes. The depth distributions of fish within the forebays of the dams were significantly different from fish passing the mid-reach reservoir. Fish residing deeper in the forebay tended to pass the dam using deeper powerhouse routes. This difference in depth distributions indicated that the depth distribution of fish at the mid-reach reservoir was not related to behaviors of fish passing through certain routes of the adjacent dams. For fish that were detected deeper than 17.5 m in the forebays, the probability of powerhouse passage (i.e., turbine) increased significantly. Another important finding was the variation in depth distributions during dam passage associated with the diel period, especially the crepuscular periods.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2014

Pressure-induced reversal between thermal contraction and expansion in ferroelectric PbTiO3

Materials with zero/near zero thermal expansion coefficients are technologically important for applications in thermal management and engineering. To date, this class of materials can only be produced by chemical routes, either by changing chemical compositions or by composting materials with positive and negative thermal expansion. Here, we report for the first time a physical route to achieve near zero thermal expansion through application of pressure. In the stability field of tetragonal PbTiO3 we observed pressure-induced reversals between thermal contraction and expansion between ambient pressure and 0.9 GPa. This hybrid behavior leads to a mathematically infinite number of crossover points in the pressure-volume-temperature space and near-zero thermal expansion coefficients comparable to or even smaller than those attained by chemical routes. The observed pressures for this unusual phenomenon are within a small range of 0.1– 0.9 GPa, potentially feasible for designing stress-engineered materials, such as thin films and nano-crystals, for thermal management applications.

FERROELECTRICS AND MULTIFERROICS↗
DOE OSTI2016

The conversion of CO 2 to methanol on orthorhombic β-Mo 2 C and Cu/β-Mo 2 C catalysts: Mechanism for admetal induced change in the selectivity and activity

Here, the conversion of CO 2 into methanol catalyzed by β-Mo 2 C and Cu/β-Mo 2 C surfaces has been investigated by means of a combined experimental and theoretical study. Experiments have shown the direct activation and dissociation of the CO 2 molecule on bare β-Mo 2 C, whereas on Cu/β-Mo 2 C, CO 2 must be assisted by hydrogen for its conversion. Methane and CO are the main products on the clean surface and methanol production is lower. However, the deposition of Cu clusters avoids methane formation and increases methanol production even above that corresponding to a model of the technical catalyst. DFT calculations on surface models of both possible C- and Mo-terminations corroborate the experimental observations. Calculations for the clean Mo-terminated surface reveal the existence of two possible routes for methane production (C + 4H → CH 4 ; CH 3 O + 3H → CH 4 + H 2 O) which are competitive with methanol synthesis, displaying slightly lower energy barriers. On the other hand, a model for Cu deposited clusters on the Mo-terminated surface points towards a new route for methanol and CO production avoiding methane formation. The new route is a direct consequence of the generation of a Mo 2 C–Cu interface. The present experimental and theoretical results entail the interesting catalytic properties of Mo 2 C as an active support of metallic nanoparticles, and also illustrate how the deposition of a metal can drastically change the activity and selectivity of a carbide substrate for CO 2 hydrogenation.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2015

Role of precursor chemistry in the direct fluorination to form titanium based conversion anodes for lithium ion batteries

In this study, a new synthetic route for the formation of titanium oxydifluoride (TiOF 2 ) through the process of direct fluorination via a fluidized bed reactor system and the associated electrochemical properties of the powders formed from this approach are reported. The flexibility of this synthetic route was demonstrated using precursor powders of titanium dioxide (TiO 2 ) nanoparticles, as well as a reduced TiO x N y . An advantage of this synthetic method is the ability to directly control the extent of fluorination as a function of reaction temperature and time. The reversible capacity of TiOF 2 anodes was found to depend greatly upon the precursor employed. The TiOF 2 synthesized from TiO 2 and TiO x N y showed reversible capacities of 300 mAh g -1 and 440 mAh g -1 , respectively, over 100 cycles. The higher reversible capacity of the TiOF 2 powders derived from TiO x N y likely relate to the partial reduction of the Ti in the fluorinated electrode material, highlighting a route to optimize the properties of conversion electrode materials.

25 ENERGY STORAGE↗
DOE OSTI2013

Numerical simulation of torus breakdown to chaos in an atmospheric-pressure dielectric barrier discharge

Understanding the routes to chaos occurring in atmospheric-pressure dielectric barrier discharge systems by changing controlling parameters is very important to predict and control the dynamical behaviors. In this paper, a route of a quasiperiodic torus to chaos via the strange nonchaotic attractor is observed in an atmospheric-pressure dielectric barrier discharge driven by triangle-wave voltage. By increasing the driving frequency, the discharge system first bifurcates to a quasiperiodic torus from a stable single periodic state, and then torus and phase-locking periodic state appear and disappear alternately. In the meantime, the torus becomes increasingly wrinkling and stretching, and gradually approaches a fractal structure with the nonpositive largest Lyapunov exponent, i.e., a strange nonchaotic attractor. After that, the discharge system enters into chaotic state. If the driving frequency is further increased, another well known route of period-doubling bifurcation to chaos is also observed.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2014

Nonlinear physics of shear Alfvén waves

Shear Alfvén waves (SAW) play fundamental roles in thermonuclear plasmas of fusion interest, since they are readily excited by energetic particles in the MeV range as well as by the thermal plasma components. Thus, understanding fluctuation induced transport in burning plasmas requires understanding nonlinear SAW physics. There exist two possible routes to nonlinear SAW physics: (i) wave-wave interactions and the resultant spectral energy transfer; (ii) nonlinear wave-particle interactions of SAW instabilities with energetic particles. Within the first route, it is advantageous to understand and describe nonlinear processes in term of proximity of the system to the Alfvénic state, where wave-wave interactions are minimized due to the cancellation of Reynolds and Maxwell stresses. Here, various wave-wave nonlinear dynamics are elucidated in terms of how they break the Alfvénic state. In particular, we discuss the qualitative and quantitative modification of the SAW parametric decay process due to finite ion compressibility and finite ion Larmor radius. We also show that toroidal geometry plays a crucial role in the nonlinear excitation of zonal structures by Alfvén eigenmodes. Within the second route, the coherent nonlinear dynamics of structures in the energetic particle phase space, by which secular resonant particle transport can occur on meso- and macro-scales, must be addressed and understood. These 'nonlinear equilibria' or 'phase-space zonal structures' dynamically evolve on characteristic (fluctuation induced) turbulent transport time scales, which are generally of the same order of the nonlinear time scale of the underlying fluctuations. In this work, we introduce the general structure of nonlinear Schrödinger equations with complex integro-differential nonlinear terms, which govern these physical processes. To elucidate all these aspects, theoretical analyses are presented together with numerical simulation results.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗