Hybrid Molecular/Inorganic Modification of Nanoporous Black Silicon
This poster covers the inspiration and project goals to understand the effect of molecular dipoles and oxide layers on textured semiconductor surfaces.
14 SOLAR ENERGY↗
SEARCH · Engineering Papers
Results for “MODIFICATIONS”
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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Keeping cool while planning a major cooling system modification for a large base-loaded power plant
This paper addresses vital considerations which need to be addressed to help ensure that the wisest approach is used for evaluating or modifying existing open or closed cycle cooling systems. (authors)
22 GENERAL STUDIES OF NUCLEAR REACTORS↗
Current status on plastic scintillators modifications
Recent developments of plastic scintillators are reviewed, from 2000 to March 2015. All examples are distributed into the main purpose, i.e. the nature of the radionuclide provided with the scope of detection of various radiation particles. The main characteristics of these newly created scintillators and their detection properties are given. (authors)
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
Modification of an Agitated Tube Reactor for use in the Reprocessing of Spent Nuclear Fuel
Aims: Convert an Agitated Tube Reactor (ATR) into a counter-current solvent extraction device. Assess effect of liquid fill level on liquid dispersion. The agitated tube reactor (ATR) is an array of connected tubes. The ATR laterally shakes in a sinusoidal path, moving the agitator bar to create mixing. Originally designed by AM Technology as a cocurrent reactor, the ATR has many features that are potentially useful in the nuclear industry: Tubes are connected by non-moving seals; Reduction in seal damage and reduced risk of expensive repairs in radioactive environments; Minimal axial dispersion within a tube; Plug flow; Narrower residence time distributions that traditional technology; Multiple tubes allow for multiple reactions in series; Converting to a counter-current design allows the ATR to be used for solvent extraction; Reprocessing or decommissioning. A 180 ml PERSPEX ATR tube with no liquid flow through was constructed and filled with a 1:1 solvent:aqueous ratio of kerosene and water. The tube was filled such that the total liquid filled 25 %, 50 %, 75 % or 100 % of the tube. A Photron Fastcam SA5, positioned at the side and the end of the tube was set to a frame rate of 5400 fps with a resolution of 1024 x 1024 and 6000 fps with a resolution of 1024 x 896 respectively. Droplets were recorded after 2 minutes of shaking to ensure good mixing. Droplet sizes are used to determine optimum fill level in the ATR. The shaking frequency follows a sinusoidal path and was set to 5 Hz. The images shown in the results section were taken at the peak of the sinusoidal motion. To convert to a counter-current design the two liquids need to be separated at the end of each tube. Liquids have been allowed to separate under gravity separation. Inclusion of baffles to reduce remixing by sloshing. Wall with height corresponding to 25 % fill volume allows kerosene to overflow into separate outlet. Increase in liquid fill level decreases the dispersion of the two liquid phases. Higher dispersion of droplets decreases surface area and therefore increases mass transfer in solvent extraction. 25 % should provide the greatest mass transfer though more work needs to completed to confirm this.
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
Achieving reasonable confidence in the validation of control room designs and modifications: A summary of the 2015 NEA experts' workshop - 124
Defining and achieving reasonable confidence in the validation of nuclear power plant control room designs is a complex challenge for many reasons; not the least of which is that validation is a test of strength rather than a test of truth. In 2015, the Nuclear Energy Agency, Committee for Safety of Nuclear Installations' Working Group on Human and Organizational Factors (WGHOF) hosted an experts' workshop to identify and critically examine potential means to address the challenge of achieving reasonable confidence in control room design validations. The experts' principal task was to answer four challenge questions. (1) What are the critical considerations in defining validation objectives and how do these impact achieving reasonable confidence? (2) What methods, approaches, resources, or rationales might be used for deriving performance requirements, selecting measures, and establishing acceptance criteria so as to support reasonable confidence? (3) What methods might be used to develop scenarios that maximize the amount and relevance of information in support of the validation conclusions and achieving reasonable confidence? (4) How should the validation results be aggregated and analyzed to determine the final validation conclusions? This paper provides an overview of the experts' responses to these challenges and briefly touches upon their implications for future directions. (authors)
22 GENERAL STUDIES OF NUCLEAR REACTORS↗
Internship Presentation: Reactor System Facility Modification to Detect Compromised Human Machine Interfaces
This study presents a multi-layered Industrial Control System (ICS)/Operational Technology (OT) security architecture aimed at detecting and mitigating compromised Human Machine Interface (HMI) and Instrumentation & Control (I&C) systems within the Flowing Autoclave System (FAS) at Idaho National Laboratory (INL). The approach combines network security solutions, hash-based algorithms, and blockchain technologies to verify system integrity and provide an immutable record of network activity. This integrated three-pronged strategy enhances the detection of system compromises, enabling preemptive action before significant damage occurs.
21 - SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLAN↗
Modification of the loss cone for energetic particles
Abstract The optimal pitch angle which maximizes the penetration distance, along the magnetic field, of relativistic charged particles injected from the midplane of an axisymmetric field is investigated analytically and numerically. Higher‐order terms of the magnetic moment invariant are necessary to correctly determine the mirror point of trapped energetic particles, and therefore the loss cone. The modified loss cone resulting from the inclusion of higher‐order terms is no longer entirely defined by the pitch angle but also by the phase angle of the particle at the point of injection. The optimal orientation of the injection has a nonzero component perpendicular to the magnetic field line, and is in the plane tangential to the flux surface. Numerical integration of particle orbits were carried out for a relativistic electron in a dipole field, showing agreement with analytic expressions. The results are relevant to experiments, which are concerned with injection of relativistic beams into the atmosphere from aboard a spacecraft in the magnetosphere.
Porazik, Peter↗
Compositional Modifications to Alter and Suppress Laves Phases in Al x CrMoTa y Ti Alloys
The development of refractory complex concentrated alloys in the Al–Cr–Mo–Ta–Ti alloy system is reported. Alloys with modified Al and Ta concentrations are designed using CALPHAD tools and produced via arc melting and characterized in both as-cast and annealed forms. Properties of the alloys, nature of the microstructures, and phase transformation behavior are described via X-ray diffraction, microstructural characterization, microhardness, and differential scanning calorimetry. Two alloys, namely, Al 0.25 CrMoTa 0.8 Ti and Al 0.75 CrMoTa 0.8 Ti, are represented by a body-centered-cubic matrix phase after annealing, along with a secondary Cr–Ta Laves phase of the C15 and C14 polytypes, respectively. In as-cast and annealed forms, the Al 0.75 CrMoTa 0.45 Ti alloy comprises a single-bcc phase. Microhardness of the Laves phase containing alloys demonstrates susceptibility to cracking, whereas the Al 0.75 CrMoTa 0.45 Ti alloy displays high specific hardness, signs of ductility as evidenced by slip traces near indentations, and minimal scatter of hardness values.
36 MATERIALS SCIENCE↗
Enabling Stable High‐Voltage LiCoO 2 Operation by Using Synergetic Interfacial Modification Strategy
Abstract Structural and interfacial instability of the LiCoO 2 cathode under a voltage exceeding 4.5 V (vs Li/Li + ) severely hinders its practical applications for high‐energy‐density lithium batteries. Herein, a modified electrolyte with nitriles (suberonitrile or 1,3,6‐hexanetricarbonitrile) and fluoroethylene carbonate (FEC) coadditives is demonstrated to form an ultrathin and uniform interface layer on LiCoO 2 cathode under a synergetic effect. As such, LiCoO 2 /Li cells display excellent cyclability at a cutoff voltage of 4.6 V with a capacity retention over 72% after 300 cycles and 60% after 200 cycles at 30 and 55 °C, respectively, even achieving operation at a high current rate (10 C) upon 500 cycles as compared to the controls with fast‐falling capacity to zero. Furthermore, an adsorption‐coordination mechanism between nitriles and cobalt and synergetic effect of coadditives are explored by the alliance of spectroscopic analysis and theoretical calculations. The contributed lone‐pairs on the N 2p orbital of nitriles in coordination lowers the real oxidation state of Co 3+/4+ so that it decreases its catalysis on electrolytes, and the synergy from nitrile‐derived species regulates FEC to form an LiF‐containing electron‐insulated interface layer. This work shares a new insight to nitriles with the synergy of coadditives and paves a way to refine (ultra)high‐voltage LiCoO 2 cathode for high‐energy‐density energy storages.
Yang, Xuerui↗
Hybrid Doping Strategy with High‐Entropy Cu/Fe Surface Modification and Zr Bulk Incorporation for Ni‐Rich Cathodes
A hybrid doping strategy combining Zr 4+ bulk doping with high-entropy Cu 2+ /Fe 3+ surface doping is developed to enhance the structural and interfacial stability of Ni-rich layered oxide cathodes. Cu and Fe are selectively introduced at the particle surface via a surface-selective ion-exchange process, forming a ≈15 nm Fe-rich layer while preserving the layered framework. Compared to the pristine cathode, the hybrid sample exhibits significantly improved electrochemical performance in both half-cell and full-cell configurations. In half-cells, the hybrid retains 88.5% and 90.2% after 100 cycles at 1C under 4.6 and 4.5 V, respectively. During high-voltage full-cell cycling, the hybrid cathode maintains over 80% capacity retention, whereas the pristine counterpart retains less than 10% under identical conditions over the same cycling period. XPS, EELS, and DEMS analyses confirm improved oxygen retention, suppressed gas evolution, and stable surface chemistry, while DFT calculations indicate enhanced Me–O bonding in the selected Fe 0.75 Cu 0.25 (Mn 1/16 Co 2/16 Ni 13/16 )O 2 surface composition, which is identified through DFT-calculated mixing energy reaching a minimum at this ratio, indicating the most thermodynamically favorable configuration. In conclusion, these results demonstrate the effectiveness of this hybrid doping strategy in mitigating coupled degradation pathways in Ni-rich cathodes.
15 GEOTHERMAL ENERGY↗
Radiative Lifetime Modification of LaF 3 :Nd Nanoparticles Embedded in 3D Silicon Photonic Crystals
Explore the source record for details and available documents.
solar (photovoltaic), solid state lighting, phonon↗
Revealing Surface Modifications of Potassium-Fluoride-Treated Cu(In,Ga)Se 2 : A Study of Material Structure, Chemistry, and Photovoltaic Performance
The effects of alkali post-deposition treatments and device properties for polycrystalline thin film Cu(In,Ga)Se2 have been investigated. It is reported that these surface treatments lead to differences in interface chemistry and device properties. The behavior of defects in the space charge region as a function of different growth parameters is investigated by correlative analytical microscopy. The latter combines electron microscopy based imaging, Kelvin probe force microscopy, and atom probe tomography. Alkali treatments lead to copper depletion and consequent sharpening of the compositional profiles, and the measured electric potential differences of exposed Cu(In1-x,Gax)Se2 surfaces. Measurable differences in resistivity and potential have also been observed, which are expected to relate to the improved open-circuit voltage, fill-factor, and device efficiency. This study frames one perspective as to why post-deposition alkaline treatments lead to copper depletion, a mildly n-type semiconductor interface, and higher efficiency for a Cu(In,Ga)Se2 thin-film photovoltaic device.
14 SOLAR ENERGY↗
Reversible Modification of Rashba States in Topological Insulators at Room Temperature by Edge Functionalization
Quantum materials with novel spin textures from strong spin-orbit coupling (SOC) are essential components for a wide array of proposed spintronic devices. Topological insulators have a necessary strong SOC that imposes a unique spin texture on topological states and Rashba states that arise on the boundary, but there is no established methodology to control the spin texture reversibly. Here, it is demonstrated that functionalizing Bi 2 Se 3 films by altering the step-edge termination directly changes the strength of SOC and thereby modifies the Rashba strength of 1D edge states. Scanning tunneling microscopy/spectroscopy shows that these Rashba edge states arise and subsequently vanish through the Se functionalization and reduction process of the step edges. The observations are corroborated by density functional theory calculations, which show that a subtle chemical change of edge termination fundamentally alters the underlying electronic structure. Importantly, fully reversible and repeatable switching of Rashba edge states across multiple cycles at room temperature is experimentally demonstrated. The results imply Se functionalization as a practical method to control SOC and spin texture of quantum states in topological insulators.
Rashba edge states↗
Towards High-Performance Nonaqueous Redox Flow Electrolyte through Ionic Modification of Active Species
We will present a novel design lithium-organic non-aqueous redox flow battery based on a modified ferrocene catholyte. This RFB produced desired electrochemical performance exceeding most of the currently reported nonaqueous RFB systems.
Environmental Molecular Sciences Laboratory↗
ZIF‐8 Membrane Permselectivity Modification by Manganese(II) Acetylacetonate Vapor Treatment
Abstract Vapor‐phase treatment of ZIF‐8 membranes with manganese(II) acetylacetonate (Mn(acac) 2 ) allows permselectivity tuning. Propylene/propane selectivity increases from 31 to 210 after the Mn(acac) 2 treatment at 165 °C for 30 min, while selectivities increase from 14.6 to 242 for H 2 /CH 4 , from 2.9 to 38 for CO 2 /CH 4 , from 2.4 to 29 for CO 2 /N 2 , and from 2.9 to 7.5 for O 2 /N 2 , after Mn(acac) 2 treatment at 175 °C for 30 min. Stable equimolar propylene/propane mixture selectivity of 165 at ambient temperature and 4 bar equimolar feed with a propylene flux of 8.3×10 −4 mol m −2 s −1 is established. A control experiment excludes thermal treatment alone causing these changes. XPS analysis reveals the presence of Mn(acac) 2 on the outer surface of the vapor‐treated ZIF‐8 membranes while no other changes are detectable by X‐ray diffraction and infrared spectroscopy.
Hayashi, Mikio↗
Post-Synthetic Modification of Porphyrin-Encapsulating Metal-Organic Materials by Cooperative Addition of Inorganic Salts to Enhance CO 2 /CH 4 Selectivity
Keeping MOM: Reaction of biphenyl-3,4',5-tricarboxylate and Cd(NO 3 ) 2 in the presence of meso-tetra(N-methyl-4-pyridyl)porphine tetratosylate afforded porph@MOM-11, a microporous metal–organic material (MOM) that encapsulates cationic porphyrins and solvent in alternating open channels. Porph@MOM-11 has cation and anion binding sites that facilitate cooperative addition of inorganic salts (such as M + Cl - ) in a stoichiometric fashion.
Zhang, Zhenjie↗