Atomically Precise Crystalline Materials Based on Kinetically Inert Metal Ions via Reticular Mechanopolymerization
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99 GENERAL AND MISCELLANEOUS↗
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Experimental and Simulation Analysis of Binary Mixtures of Biomass and Inert Material
A literature review was conducted to identify experiments on various scales of biomass combustion specific to circulating fluidized bed (CFB) combustors. Typical feedstock and inert bed material characteristics for biomass combustion in a CFB were gathered. This information was used to design laboratory-scale, non-reacting experiments on biomass-inert bed material mixtures in a 1-in. cylindrical test rig in the Multiphase Flow Analysis Laboratory (MFAL) in Morgantown, WV. The biomass chosen was a hardwood. Pellets from the hardwood were milled and sieved to obtain three size ranges—small, medium, and large. Three mass loadings of each of the biomass samples were fluidized with glass beads as the inert bed material to study the mixing characteristics under varying fluidizing gas velocities. Hydrodynamic data including pressure drop measurements at select vertical locations and video recordings of the mixture behavior were generated in this effort.
09 BIOMASS FUELS↗
The use of an inert gas in an artificial environment <de l'utilite d'un gaz inerte dans une atmosphere artificielle<
Inert gas in artificial environment to prevent pulmonary disturbances
ENVIRONMENT SIMULATION↗
A Redox-Active Tetrazine-Based Pincer Ligand for the Reduction of N-Oxyanions Using a Redox-Inert Me
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Beagan, D.M.↗
Vibration mitigation using an inerter-based isolation system
Extreme dynamic environments can result in the failure of structures and equipment. To mitigate these effects, isolation systems can be used. In recent years, inerters have been studied as a part of different structural control methods. The inerter is attractive for many structural control methods because it can produce large mass effects despite having a small physical mass through the transformation of translational motion to the rotational motion of a flywheel. While inerters have been considered in structural control, experimental studies of isolation systems featuring inerters has been limited. This project seeks to study the ability of the addition of an inerter to improve the dynamic performance of isolation systems when considering a random vibration environment. The results of this study demonstrate that the inerter can have a large impact on the dynamic properties of an isolated system, including shifting the isolation mode frequency lower while reducing its amplitude. High frequency noise did result from the inclusion of the inerter but may not be of significant concern depending on the frequency range of interest. The strong performance of the inerter in a simplified isolation system observed during this work motivates future studies of inerters in isolation systems.
S.S. Abolghasemi↗
Balancing moisture and oxygen can match the crystallization dynamics of inert halide perovskite processing
Understanding crystallization in ambient environments is essential for scaling the fabrication of halide perovskite solar cells. Antisolvent-free perovskite deposition offers improved compatibility with high-throughput processing but introduces distinct crystallization dynamics relative to the more ubiquitous use of antisolvents in lab-scale perovskite fabrication. These dynamics are driven by interactions between solutes, solvent and the deposition environment. Using in situ wide-angle X-ray scattering during spin-coating and annealing, we demonstrate how relative humidity (RH) and oxygen, can be tuned to drive polytype evolution during ambient crystallization of formamidinium lead iodide to match that of inert synthesis and achieve comparable film and device quality. In an inert (N 2 ) environment, we find that perovskite films follow a well-established 2H → 3C phase transformation with a short period of coexistence of the 4H and 6H phase during heating. During crystallization in dry air (RH 0%), the added presence of oxygen leads to the dominance of 4H intermediate for an extended duration, establishing a 2H → 4H → 3C pathway. Introducing low humidity (RH 10%) suppresses the 4H phase to a short-lived intermediate above 100 °C, facilitating a more direct transition to the desired 3C phase and almost replicating the crystallization behavior observed under inert conditions. Interestingly, films crystallized under RH 10% show a lower onset temperature for the perovskite 3C phase than under N 2 . At higher humidity (RH 40%), the strong interaction of oxygen and moisture with iodoplumbates appears to stabilize higher order polytypes (4H and 6H). Devices fabricated under RH 10% achieve higher efficiency and enhanced stability compared to those produced under inert atmosphere. These findings provide mechanistic insight into crystallization pathways in different environments and provide a framework to transfer processes from inert to ambient conditions. The results highlight the critical role of controlled humidity in tuning antisolvent-free perovskite crystallization for scalable processing.
Hossain, Maimur [Univ. of California, San Diego, C↗
Effect of inert propellant injection on Mars ascent vehicle performance
A Mars ascent vehicle is limited in performance by the amount of propellant which can be brought from earth. In some cases the vehicle performance can be improved by injecting inert gas into the engine, if the inert gas is available as an in situ resource. CO2, N2 and Ar are constituents of the Martian atmosphere which are available at every point on the Martian surface and could be produced by a very simple processing technique, consisting essentially of compressing the atmosphere. The effect of inert gas injection on rocket engine performance was analyzed with a numerical code calculating chemical equilibrium in the engine, for engines of varying combustion chamber pressure, expansion ratio, oxidizer/fuel ratio, and inert injection fraction. Results of this analysis were applied to several candidate missions to determine how the required mass of return propellant needed in LEO could be decreased using inert propellant injection.
Colvin, James E.↗
Effect of inert propellant injection on Mars ascent vehicle performance
A Mars ascent vehicle is limited in performance by the propellant which can be brought from Earth. In some cases the vehicle performance can be improved by injecting inert gas into the engine, if the inert gas is available as an in-situ resource and does not have to be brought from Earth. Carbon dioxide, nitrogen, and argon are constituents of the Martian atmosphere which could be separated by compressing the atmosphere, without any chemical processing step. The effect of inert gas injection on rocket engine performance was analyzed with a numerical combustion code that calculated chemical equilibrium for engines of varying combustion chamber pressure, expansion ratio, oxidizer/fuel ratio, and inert injection fraction. Results of this analysis were applied to several candidate missions to determine how the required mass of return propellant needed in low Earth orbit could be decreased using inert propellant injection.
Colvin, James E.↗
Pulse Tube Coolers with an Inertance Tube: Theory, Modeling and Practice
We have studied the advantages to be gained by replacing the conventional orifice of a pulse tube cooler by an inertance tube - a long thin tube that introduces the possibility for additional phase shift between pressure and mass flow in the pulse tube section. The case for the use of an inertance tube is most clearly made with an electrical analogy where the 'inductance' added by the inertance tube allows for optimal power transfer at the cold heat exchanger. Detailed modeling of a pulse tube system with an inertance tube confirms these advantages. Comparison between a laboratory cooler with an orifice and with an inertance tube will be presented and reasons wily it is difficult to realize all the expected gain will be given.
Roach, Pat R.↗
Contact with Electrically Conductive Inert Solids Alters Intrinsic Heterogeneous Brønsted Acid Catalysis
Interfacial electric fields at heterogeneous catalyst surfaces have been demonstrated to alter kinetics of liquid-phase reactions. In these systems, electric fields are generated from applying a potential to the catalyst through connection to a potentiostat or through electron transfer from redox-active species in solution. Here, we demonstrate that catalyst polarization can also occur by simply contacting electrically conductive inert solids, leading to the counterintuitive conclusion that a catalyst particle touching an inert solid can alter intrinsic reaction rates. Using dehydration of 1-methylcyclopentanol to 1-methylcyclopentene catalyzed by Brønsted-acidic carboxylic acid groups on carbon nanotubes as a proof-of-concept probe reaction, we show that catalyst contact with inert, thermally reduced carbon nanotubes leads to order-of-magnitude changes in reaction rate. Furthermore, we demonstrate that these contact-induced effects can also be observed under standard laboratory reaction conditions, where particle-to-particle contact in stirred catalyst powder suspensions is sufficient to demote rates by ∼8-fold. This work provides the foundation for a new method of reaction rate control, which could have implications whenever heterogeneous catalyst particles are in contact with inert materials for liquid-phase reactions in the presence of electrolyte.
Alcohols↗
Titanium Wire Arc Additive Manufacturing Inert Enclosure and Material Handling Safety Considerations
Wire arc additive manufacturing (WAAM) via metal inert gas (MIG)/gas metal arc welding (GMAW) is a viable option for fabrication of large-scale titanium parts; however, it introduces new safety hazards associated with both the material and the additional system hardware required for the process. Localized gas shielding of the weld arc via standard GMAW torch is inadequate for titanium due to its affinity for oxygen; thereby requiring the use of an inert enclosure to protect the weld from entraining oxygen. The use of the inert enclosure presents potential safety hazards such as operator asphyxiation and brings up discussion of confined space considerations. In addition, the titanium welding process creates pyrophoric titanium soot residue around the deposit, which can undergo deflagration during part cleaning and part removal. This paper provides an overview of the titanium WAAM process along with safety considerations for the design and operation of the inert enclosure as well as functional solutions for the safe handling of the titanium soot by-product.
Walters, Alex↗
Additive manufacturing of high explosives with inert dilution for wave shaping and detonation velocity grading
The performance of a high explosive charge is highly influenced by the detonation velocity and any inherent internal structure. Additively manufactured (AM) high explosive charges allow for a precisely engineered internal structure and the selective placement of discrete or graded volumes of a tailored material, which are unachievable by conventional means. The dilution of a solid explosive by an inert additive for detonation velocity reduction is herein evaluated for a method of material extrusion called a direct-ink-write AM, where an 1,3,5,7-tetranitro-1,3,5,7-tetrazoctane-based ultraviolet -curable energetic-binder paste explosive was diluted by the inert density mock 5-iodo-2′-deoxyuridine for use in the manufacture of multi-material explosive charges. The explosive ink was characterized for printing by rheological and particle size measurements, and the detonation velocities for 0–40 wt. % inert diluent were found to have a continuous linear reduction in detonation velocity down to 14.3% difference. A two-component 3D plane wave explosive lens with 8.038 km/s “fast” and 7.491 km/s “slow” diluted ink in an internal cone demonstrated a reduced time of breakout at the output face from 361 to 53 ns. A linearly graded “fast–slow–fast” cylinder was successfully printed and fired, showing engineered control along the length of the charge as the detonation velocity dropped from 7.851 to 6.700 km/s and then recovered to 7.241 km/s. The extreme control over the internal composition of a high explosive charge via a dual-material extruder/mixer challenges conventional manufacturing approaches and opens new avenues for engineered detonation wavefronts, high explosive charge performance, and new applications.
36 MATERIALS SCIENCE↗
Observations of Atmospheric Corrosion Testing on Heated Austenitic Stainless Steel Surfaces: Exploring the Role of Inert Dust Particulates and Seawater
Relevant atmospheric corrosion laboratory testing environments were developed to explore the influence of inert dust and seawater on the corrosion susceptibility of stainless steel in spent nuclear fuel dry storage conditions. Measurements from dust collected on in-service dry storage canisters were applied to develop exposure conditions. Three atmospheric exposure conditions, two static and one cyclic, were examined with three different surface coverages: co-deposited large dust and seawater, co-deposited small dust and seawater, and solely seawater. Stainless steel coupons representative of spent nuclear fuel dry storage canister material were subjected to the various corrosion environments, with the results from exposures up to 1 year presented here. Post exposure, corrosion damage was analyzed using optical microscopy, scanning electron microscopy, and energy dispersive X-ray spectroscopy. Initial observations are presented herein, and potential implications with respect to the influence of inert dust particles on corrosion susceptibility are summarized. In general, the co-deposition of dust and salt resulted in larger pits and exhibited mixed modes of corrosion that were not observed in the no-dust conditions (i.e., crevicing, filiform, and pits within pits). The presence of the inert dust may influence brine spreading and/or act as crevice formers, leading to enhanced corrosion. This study highlights the significance of incorporating dust particulate(s) beyond the deliquescent chemistries to fully evaluate atmospheric corrosion severity.
Sea salt↗
Comparison of inert-gas-fusion and modified Kjeldahl techniques for determination of nitrogen in niobium alloys
This report compares results obtained for the determination of nitrogen in a selected group of niobium-base alloys by the inert-gas-fusion and the Kjeldahl procedures. In the inert-gas-fusion procedure the sample is heated to approximately 2700 C in a helium atmosphere in a single-use graphite crucible. A platinum flux is used to facilitate melting of the sample. The Kjeldahl method consisted of a rapid decomposition with a mixture of hydrofluoric acid, phosphoric acid, and potassium chromate; distillation in the presence of sodium hydroxide; and highly sensitive spectrophotometry with nitroprusside-catalyzed indophenol. In the 30- to 80-ppm range, the relative standard deviation was 5 to 7 percent for the inert-gas-fusion procedure and 2 to 8 percent for the Kjeldahl procedure. The agreement of the nitrogen results obtained by the two techniques is considered satisfactory.
Merkle, E. J.↗
Inert gases in Sea of Fertility regolith
The content and isotopic composition were studied of inert gases -- He, Ne, Ar, Kr, and Xe -- in samples of lunar regolith returned by the Luna 16 automatic station. The samples were taken from depths of about 12 and 30 cm. The high concentrations of inert gases exceed by several orders their concentrations observed in ordinary stony meteorites. The gases in lunar regolith were a complex mixture of gases of different origins: Solar, cosmogenic, radiogenic, and so on. Solar wind gases predominated, distributed in the thin surficial layer of the regolith grains. The concentrations of these gases in the surficial layer is several cubic centimeters per gram. The isotopic composition of the inert gases of solar origin approaches their composition measured in gas-rich meteorites.
Vinogradov, A. P.↗
A method for determining optimum phasing of a multiphase propulsion system for a single-stage vehicle with linearized inert weight
A general analytical treatment is presented of a single-stage vehicle with multiple propulsion phases. A closed-form solution for the cost and for the performance and a derivation of the optimal phasing of the propulsion are included. Linearized variations in the inert weight elements are included, and the function to be minimized can be selected. The derivation of optimal phasing results in a set of nonlinear algebraic equations for optimal fuel volumes, for which a solution method is outlined. Three specific example cases are analyzed: minimum gross lift-off weight, minimum inert weight, and a minimized general function for a two-phase vehicle. The results for the two-phase vehicle are applied to the dual-fuel rocket. Comparisons with single-fuel vehicles indicate that dual-fuel vehicles can have lower inert weight either by development of a dual-fuel engine or by parallel burning of separate engines from lift-off.
Martin, J. A.↗
Inert gas thrusters
Inert gas thrusters considered for space propulsion systems were investigated. Electron diffusion across a magnetic field was examined utilizing a basic model. The production of doubly charged ions was correlated using only overall performance parameters. The use of this correlation is therefore possible in the design stage of large gas thrusters, where detailed plasma properties are not available. Argon hollow cathode performance was investigated over a range of emission currents, with the positions of the inert, keeper, and anode varied. A general trend observed was that the maximum ratio of emission to flow rate increased at higher propellant flow rates. It was also found that an enclosed keeper enhances maximum cathode emission at high flow rates. The maximum cathode emission at a given flow rate was associated with a noisy high voltage mode. Although this mode has some similarities to the plume mode found at low flows and emissions, it is encountered by being initially in the spot mode and increasing emission. A detailed analysis of large, inert-gas thruster performance was carried out. For maximum thruster efficiency, the optimum beam diameter increases from less than a meter at under 2000 sec specific impulse to several meters at 10,000 sec. The corresponding range in input power ranges from several kilowatts to megawatts.
Kaufman, H. R.↗