Slides on AFC-4C-R5 MNT20E destructive PIE :SEM, Micro-tensile testing, Post-test TEM Characterization
Slides containing updated PIE results for AFC-4C-R5 (MNT20E)
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
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Rational Design of Novel Biomimetic Sequence-Defined Polymers for Mineralization Applications
Silica biomineralization is a naturally occurring process, wherein organisms use proteins and other biological structures to direct the formation of complex, hierarchical nanostructures. Discovery and characterization of such proteins and their underlying mechanisms spurred significant efforts to identify routes for biomimetic mineralization that reproduce the exquisite shapes and size selectivities found in nature. A common strategy has been the use of short peptide sequences with chemistry mimicking those found in natural systems, such as the use of the silaffin-derived R5 peptide. While progress has been made using this approach, there are many limitations that have prevented breakthroughs in biomimicry. To advance our ability to use charged macromolecules for silica formation, we propose to use sequence-defined synthetic polymers known as peptoids, or N-substituted polyglycines, which present significant capability for the precise tuning of sequence and structure beyond what can often be achieved with peptides alone. This study presents a computationally predicted design of these polymers that leads to the controlled formation of silica nanomaterials. We investigate surface adsorption and the mineralization process through analysis of binding mechanisms and energetics of the R5 system. Next, we synthesized two R5-inspired peptoids and validated our prediction in the design of mineralization polymers through characterization using surface plasmon resonance and electron microscopy. Here, this computationally guided study holds great promise for designing new sequences with unprecedented control of the placement of chemical functional groups, thus allowing for further unraveling of silicification mechanisms and the eventual design of sequence-defined synthetic polymers leading to the predictive synthesis of nanostructured functional materials.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Development of a Markerless Deletion Mutagenesis System in Nitrate-Reducing Bacterium Rhodanobacter denitrificans
Rhodanobacter has been found as the dominant genus in aquifers contaminated with high concentrations of nitrate and uranium in Oak Ridge, TN, USA. The in situ stimulation of denitrification has been proposed as a potential method to remediate nitrate and uranium contamination. Among the Rhodanobacter species, Rhodanobacter denitrificans strains have been reported to be capable of denitrification and contain abundant metal resistance genes. However, due to the lack of a mutagenesis system in these strains, our understanding of the mechanisms underlying low-pH resistance and the ability to dominate in the contaminated environment remains limited. Here, we developed an in-frame markerless deletion system in two R. denitrificans strains. First, we optimized the growth conditions, tested antibiotic resistance, and determined appropriate transformation parameters in 10 Rhodanobacter strains. We then deleted the upp gene, which encodes uracil phosphoribosyltransferase, in R. denitrificans strains FW104-R3 and FW104-R5. The resulting strains were designated R3_Δupp and R5_Δupp and used as host strains for mutagenesis with 5-fluorouracil (5-FU) resistance as the counterselection marker to generate markerless deletion mutants. Further, to test the developed protocol, the narG gene encoding nitrate reductase was knocked out in the R3_Δupp and R5_Δupp host strains. As expected, the narG mutants could not grow in anoxic medium with nitrate as the electron acceptor. Overall, these results show that the in-frame markerless deletion system is effective in two R. denitrificans strains, which will allow for future functional genomic studies in these strains furthering our understanding of the metabolic and resistance mechanisms present in Rhodanobacter species.
59 BASIC BIOLOGICAL SCIENCES↗
Modeling–Experiment–Theory Analysis of Reactions Initiated from Cl + Methyl Formate
Methyl formate (MF; CH 3 OCHO) is the smallest representative of esters, which are common components of biodiesel. The present study characterizes the thermal dissociation kinetics of the radicals formed by H atom abstraction from MF—CH 3 OCO and CH 2 OCHO—through a combination of modeling, experiment, and theory. For the experimental effort, excimer laser photolysis of Cl 2 was used as a source of Cl atoms to initiate reactions with MF in the gas phase. Time-resolved species profiles of MF, Cl 2 , HCl, CO 2 , CH 3 , CH 3 Cl, CH 2 O, and CH 2 ClOCHO were measured and quantified using photoionization mass spectrometry at temperatures of 400–750 K and 10 Torr. The experimental data were simulated using a kinetic model, which was informed by ab initio-based theoretical kinetics calculations and included chlorine chemistry and secondary reactions of radical decomposition products. Here, we calculated the rate coefficients for the H-abstraction reactions Cl + MF → HCl + CH 3 OCO (R1a) and Cl + MF → HCl + CH 2 OCHO (R1b): k 1a,theory = 6.71 × 10 –15 ·T 1.14 ·exp(—606/T) cm 3 /molecule·s; k 1b,theory = 4.67 × 10 –18 ·T 2.21 ·exp(—245/T) cm 3 /molecule·s over T = 200–2000 K. Electronic structure calculations indicate that the barriers to CH 3 OCO and CH 2 OCHO dissociation are 13.7 and 31.6 kcal/mol and lead to CH 3 + CO 2 (R3) and CH 2 O + HCO (R5), respectively. The master equation-based theoretical rate coefficients are k 3,theory (P = ∞) = 2.94 × 10 9 ·T 1.21 ·exp(—6209/T) s –1 and k 5,theory (P = ∞) = 8.45 × 10 8 ·T 1.39 ·exp(—15132/T) s –1 over T = 300–1500 K. The calculated branching fractions into R1a and R1b and the rate coefficient for R5 were validated by modeling of the experimental species time profiles and found to be in excellent agreement with theory. Additionally, we found that the bimolecular reactions CH 2 OCHO + Cl, CH 2 OCHO + Cl 2 , and CH 3 + Cl 2 were critical to accurately model the experimental data and constrain the kinetics of MF-radicals. Inclusion of the kinetic parameters determined in this study showed a significant impact on combustion simulations of larger methyl esters, which are considered as biodiesel surrogates.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Rate constants and third-body collision efficiencies for recombination of Na with OH and O2: Implications for flame inhibition by alkali salts
Flame inhibition by alkali metals has implications for solid fuel combustion, fire safety, and a number of industrial processes. While the mechanism of inhibition is fairly well understood, details related to thermodynamic properties and rate constants are still in question. In the present work, the recombination of Na with OH (R5) and O2 (R7), respectively, was characterized theoretically, and the implications for modeling laminar premixed hydrogen flames doped with sodium species were examined. Third-body collision efficiencies and low-pressure-limit rate constants were obtained using newly fitted ab initio-based potential energy surfaces, classical trajectories, and one-dimensional master equation calculations. The results are consistent with available experimental results and aid in the present modeling study by providing rate information for bath gases and conditions that remain unexplored experimentally. Chemical kinetic modeling of relative Na and absolute H and OH profiles in H2-fueled laminar, premixed flames doped with a sodium salt shows that the most important radical removal cycle is the sequence Na + OH (+M) → NaOH (+M) (R5), NaOH + H → Na + H2O (R12), even under oxidizing conditions. A secondary cycle, Na + O2 (+M) ⇄ NaO2 (+M) (R7), NaO2 + OH → NaOH + O2 (R14), is less important due to the low thermal stability of NaO2. In most flames, reaction R7 is partially equilibrated, and reaction R14 becomes rate-limiting for the second cycle. The flame analysis supports a lower value of k14 than indicated by recent work on KO2 + OH, but more work is required to confirm this.
Jasper, Ahren W.↗
Specifications and pre-production of n + -in-p large-format strip sensors fabricated in 6-inch silicon wafers, ATLAS18, for the Inner Tracker of the ATLAS Detector for High-Luminosity Large Hadron Collider
Abstract The ATLAS experiment is constructing new all-silicon inner tracking system for HL-LHC. The strip detectors cover the radial extent of 40 to 100 cm. A new approach is adopted to use p-type silicon material, making the readout in n + -strips, so-called n + -in-p sensors. This allows for enhanced radiation tolerance against an order of magnitude higher particle fluence compared to the LHC. To cope with varying hit rates and occupancies as a function of radial distance, there are two barrel sensor types, the short strips (SS) for the inner 2 and the long strips (LS) for the outer 2 barrel cylinders, respectively. The barrel sensors exhibit a square, 9.8 × 9.8 cm 2 , geometry, the largest possible sensor area from a 6-inch wafer. The strips are laid out in parallel with a strip pitch of 75.5 μm and 4 or 2 rows of strip segments. The strips are AC-coupled and biased via polysilicon resistors. The endcap sensors employ a “stereo-annulus” geometry exhibiting a skewed-trapezoid shapes with circular edges. They are designed in 6 unique shapes, R0 to R5, corresponding to progressively increasing radial extents and which allows them to fit within the petal geometry and the 6-inch wafer maximally. The strips are in fan-out geometry with an in-built rotation angle, with a mean pitch of approximately 75 μm and 4 or 2 rows of strip segments. The eight sensor types are labeled as ATLAS18xx where xx stands for SS, LS, and R0 to R5. According to the mechanical and electrical specifications, CAD files for wafer processing were laid out, following the successful designs of prototype barrel and endcap sensors, together with a number of optimizations. A pre-production was carried out prior to the full production of the wafers. The quality of the sensors is reviewed and judged excellent through the test results carried out by vendor. These sensors are used for establishing acceptance procedures and to evaluate their performance in the ATLAS collaboration, and subsequently for pre-production of strip modules and stave and petal structures.
Instruments & Instrumentation↗
Method for preparing bis-(silylalkyl)carbonate esters
Carbonate esters of Formula (I): (R1)(R2)(R3)Si—R4—O—C(═O)—O—R4—Si(R1)(R2)(R3) are prepared by reaction of a silyl-substituted alcohol of Formula (II): (R1)(R2)(R3)Si—R4—OH with an activated carbonyl compound of Formula (III): C(═O)Z2 in the presence of a catalyst (e.g., an bicyclic amidine, a bicyclic guanidine, or a phosphazene) in an aprotic solvent. In Formulas (I) and (II) each of R1 and R2 independently is alkyl; R3 is alkyl or —X1—Si(R5)(R6)(R7); X1 is O or alkylene; R4 is alkylene; and each R5, R6, and R7 independently is alkyl. In Formula (III), Z is 1-N-imidazolyl or 1-N-succinimidyl. In some embodiments, the catalyst used in the methods described herein comprises at least one base selected from the group consisting of a bicyclic amidine and a bicyclic guanidine. The reaction proceeds readily under both bulk and continuous flow reactor conditions.
25 ENERGY STORAGE↗
Solvent for non-aqueous battery
A solvent useful for lithium batteries comprises a compound of Formula (I): (R1)(R2)(R3)Si—R4—O—C(O)—[(O—R5)n—(O—C(O)]m—O—R6—X1. Each of R1 and R2 independently is alkyl; R3 is alkyl, —X2—Si(R7)(R8)(R9), or —CH2—O—C(O)—O—R10; X1 is H or —Si(R11)(R12)(R13); each of R4 and R6 independently is alkylene; each R5 independently is C2 to C6 alkylene; each of R7, R8, R9, and R10 independently is alkyl; X2 is O or alkylene; each of R11 and R12 independently is alkyl; R13 is alkyl or —X3—Si(R14)(R15)(R16); each of R14, R15, and R16 independently is alkyl; X3 is O or alkylene; m is 0 or 1, and n is 1-3; and when m is 0 and R3 is alkyl, X1 is —Si(R11)(R12)(R13). Also described is a method for manufacturing a compound of Formula (II): (R17)(R18)(R19)Si—CH2—O—C(O)—O—R20 where each R17, R18, R19, and R20 is alkyl.
25 ENERGY STORAGE↗
Phase Control of Nanocrystalline Inclusions in Bioprecipitated Titania with a Panel of Mutant Silica-Binding Proteins
The biomimetic route to inorganic synthesis presents an opportunity to produce complex materials with superior properties under ambient conditions and from nontoxic precursors. While there has been significant progress in using solid-binding peptides (SBPs), proteins, and organisms to produce a variety of inorganic and hybrid structures, it has been more challenging to understand the interplay of solution conditions and solid-binding peptide (SBP) sequence, structure, and self-association on synthetic outcomes. Here, we show that fusing the Car9 silica-binding peptide—but not the silaffin-derived R5 peptide—to superfolder green fluorescent protein (sfGFP) enhances the ability of micromolar concentrations of protein to induce rapid titania (TiO 2 ) precipitation from acidified solutions of tetrakis(di-lactato)-oxo-titanate (TiBALDH). TiO 2 is produced stoichiometrically and although predominantly amorphous, contains nanosized anatase and monoclinic TiO 2 (B) inclusions. Remarkably, the phase of these nanocrystallites can be tuned from about 80% TiO 2 (B) to about 65% anatase by using Car9 mutants impaired in their ability to drive the formation of higher-order sfGFP-Car9 oligomers. Our results suggest that the presentation of multiple basic side chains in an extended plane formed by SBP self-association is critical to template the formation of monoclinic crystallites and underscore the subtle influence that single or dual substitutions in dodecameric SBPs can exert on the yield and crystallinity of biomineralized inorganics.
mutagenesis↗
Utilizing Machine Learning to Improve Neutralization Potency of an HIV-1 Antibody Targeting the gp41 N-Heptad Repeat
The N-heptad repeat (NHR) of the HIV-1 gp41 prehairpin intermediate (PHI) is an attractive potential vaccine target with high sequence conservation across diverse strains. However, despite the potency of NHR-targeting peptides and clinical efficacy of the NHR-targeting entry inhibitor enfuvirtide, no potently neutralizing NHR-directed monoclonal antibodies (mAbs) nor antisera have been identified or elicited to date. The lack of potent NHR-binding mAbs both dampens enthusiasm for vaccine development efforts at this target and presents a barrier to performing passive immunization experiments with NHR-targeting antibodies. To address this challenge, we previously developed an improved variant of the NHR-directed mAb D5, called D5_AR, which is capable of neutralizing diverse tier-2 viruses. Building on that work, here we present the 2.7Å-crystal structure of D5_AR bound to NHR mimetic peptide IQN17. We then utilize protein language models and supervised machine learning to generate small (n < 100) libraries of D5_AR variants that are subsequently screened for improved neutralization potency. We identify a variant with 5-fold improved neutralization potency, D5_FI, which is the most potent NHR-directed monoclonal antibody characterized to date and exhibits broad neutralization of tier-2 and −3 pseudoviruses as well as replicating R5 and X4 challenge strains. Additionally, our work highlights the ability of protein language models to efficiently identify improved mAb variants from relatively small libraries.
Biopolymers↗
Mechanical testing of PH13-8Mo H950 Steel for Xue-Wierzbicki Fracture Criterion Determination at 20° C and -40° C
Mechanical testing was conducted to collect the data needed to build a Xue-Wierzbicki (XW) fracture model for PH13-8 Mo H950 stainless steel (PH 13-8 SS). This model is intended for use in structural analysis of this material between room temperature and -40° C. Tests were performed on four different specimen geometries such that a range of stress states were characterized at room temperature and -40° C. Tensile tests on R5 tensile specimens were also performed to assess material anisotropy. Fracture toughness test were also conducted. The fracture toughness of this material at -40° C was 68% of the room-temperature value. Material strength generally increased with decreasing temperature while the opposite trend was observed for ductility. These trends were most pronounced for specimens with the largest stress triaxialities.
36 MATERIALS SCIENCE↗
Environmental creep-fatigue and weld creep cracking: a summary of design and fitness-for-service practices
This report surveys current creep-fatigue design and fitness-for-service assessment procedures, with a particular focus on environmental effects and creep-fatigue cracking near weldments. Included in this assessment are the American Society of Mechanical Engineers Boiler and Pressure Vessel Code Section III, Division 5, the British R5 standard, the French RCC-MRx design code, the ITER Structural Design Criteria, and the API-579/ASME FFS-1 fitness-for-service rules for petrochemical components. The focus of this review is to identify gaps in the available methods that could prevent regulators from evaluating future high temperature reactor designs. The report makes recommendations, where appropriate, on actions that could be taken to fill these gaps by either providing adequate assessment procedures for creep-fatigue damage in harsh environments or by evaluating strategies vendors could use to mitigate regulatory concerns with creep-fatigue damage in high temperature reactor components.
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
Nanoporous Wood Chips Based Sizable, Robust, and Low-Cost Honeycomb Vacuum Insulation Panels (DOE BENEFIT Final Research Performance Progress Report (RPPR))
Conventional vacuum insulation panels (VIPs) suffer from severe limitations including high cost, vulnerability to perforation, and significant performance degradation over time due to vacuum loss. InventWood Inc. (IW) and partnering teams completely re-engineered the VIP structure by constructing arrays of isolated vacuum-cells to enable limited cutting at designated areas (in between vacuum cells) and reduced consequential vacuum loss due to puncture. The teams also replaced the expensive vacuum insulation core materials with a low-cost commercial wood pulp and recycled long fiber. The wood pulp derived VIP can deliver an overall panel insulation of R15 (<0.01W/m·K) with over 90% thermal resistance retention after cutting (R13.5 overall, R5 along the cut edges). In addition, the vacuum-cell-array design minimizes edge losses, resulting in more durable performance, longer service life (>50 years), and higher R-value per dollar towards a cost target of <$1/ft 2 ·in. It is anticipated that the Nanochip-VIP will attract strong market interest and become an affordable insulation solution for energy efficient buildings and retrofits, leading to significant reductions in energy usage.
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
Methods of producing metal sulfides, metal selenides, and metal sulfides/selenides having controlled architectures using kinetic control
The present invention is directed to methods of preparing metal sulfide, metal selenide, or metal sulfide/selenide nanoparticles and the products derived therefrom. In various embodiments, the nanoparticles are derived from the reaction between precursor metal salts and certain sulfur- and/or selenium-containing precursors each independently having a structure of Formula (I), (II), or (III), or an isomer, salt, or tautomer thereof, where Q1, Q2, Q3, R1, R2, R3, R5, and X are defined within the specification.
36 MATERIALS SCIENCE↗
Conversion of dicarboxylic acids to monomers and plasticizers
The present disclosure relates to a composition that includes a first repeat unit defined by where R includes a first hydrocarbon chain that includes at least one olefinic bond, R5 includes a second hydrocarbon chain, the second hydrocarbon chain may be saturated, and n may be between 2 and 1,000.
36 MATERIALS SCIENCE↗
Methods for making bacteriochlorin macrocycles comprising an annulated isocyclic ring and related compounds
Described herein are bacteriochlorins comprising an annulated isocyclic ring such as a compound Formula I: or a metal conjugate thereof, wherein: R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, R12, R13, R14, R15, R16, and Z are each as defined herein. Also described are methods and intermediates for the synthesis of bacteriochlorins comprising an annulated isocyclic ring, and methods of using such bacteriochlorins for, among other things, diagnostic and therapeutic purposes such as, e.g., luminescent compounds in flow cytometry, and/or as active agents in photodynamic therapy (PDT).
Lindsey, Jonathan S.↗
Molecules and oligomers for endothermic singlet fission
The present disclosure relates to a composition that includes a repeat unit defined by where each of R1, R2, R3, R4, R5, R6, R7, and R8 includes at least one of a hydrogen atom, a fluorine atom, and/or a first hydrocarbon chain having between 1 and 20 carbon atoms, inclusively, where each of A1, A2, A3 and A4 are either a carbon atom or a nitrogen atom, when A1 is a nitrogen atom, A2 is a carbon atom, when A2 is a nitrogen atom, A1 is a carbon atom, when A3 is a nitrogen atom, A4 is a carbon atom, when A4 is a nitrogen atom, A3 is a carbon atom, either A1 or A2 form a covalent bond, x, with a carbon atom, a, either A3 or A4 form a covalent bond, y, with a carbon atom, b, L is a linker group that includes an aromatic ring, and n is between 1 and 20, inclusively.
Korovina, Nadezhda↗
Lipophilic diglycolamide compounds for extraction of rare earth metals from aqueous solutions
A method for extracting rare earth metals (e.g., lanthanides and/or actinides) from aqueous solution, the method comprising: (i) acidifying an aqueous solution containing said rare earth metals with sulfuric acid to result in an acidified aqueous solution containing 1-12 M concentration of sulfuric acid; and (ii) contacting the acidified aqueous solution with an aqueous-insoluble hydrophobic solution comprising a rare earth extractant molecule dissolved in an aqueous-insoluble hydrophobic solvent to result in extraction of one or more of the rare earth metals into the aqueous hydrophobic solution, wherein the rare earth extractant molecule has the following structure: wherein R1, R2, R3, and R4 are independently selected from hydrocarbon groups containing 1-20 carbon atoms, provided that the total carbon atoms in R1, R2, R3, and R4 is at least 12; and R5 and R6 are independently selected from hydrogen atom and hydrocarbon groups containing 1-3 carbon atoms.
Brigham, Derek↗