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1. Performance of Carbide Alloy Compounds in Carbon Doped MoNbTaW

   https://doi.org/10.3390/cryst11091073  

   Zhang, Congyan; Bhandari, Uttam; Lei, Jialin; Zeng, Congyuan; Guo, Shengmin; Choi, Hyunjoo; Nam, Seungjin; Yan, Jinyuan; Yang, Shizhong; Gao, Feng (September 2021, Crystals)

   In this work, the performance of the carbon doped compositionally complex alloy (CCA) MoNbTaW was studied under ambient and high pressure and high temperature conditions. TaC and NbC carbides were formed when a large concentration of carbon was introduced while synthesizing the MoNbTaW alloy. Both FCC carbides and BCC CCA phases were detected in the sample compound at room temperature, in which the BCC phase was believed to have only refractory elements MoNbTaW while FCC carbide came from TaC and NbC. Carbides in the carbon doped MoNbTaW alloy were very stable since no phase transition was obtained even under 3.1 GPa and 870 °C by employing the resistor-heating diamond anvil cell (DAC) synchrotron X-ray diffraction technique. Via in situ examination, this study confirms the stability of carbides and MoNbTaW in the carbon doped CCA even under high pressure and high temperature. 

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2. On Optimization and Counting of Non-Broken Bases of Matroids

   https://doi.org/10.4230/LIPICS.APPROX/RANDOM.2023.40  

   Abdolazimi, Dorna; Lindberg, Kasper; Gharan, Shayan Oveis (July 2023, Schloss Dagstuhl – Leibniz-Zentrum für Informatik)

   Megow, Nicole; Smith, Adam (Ed.)

   Given a matroid M = (E,I), and a total ordering over the elements E, a broken circuit is a circuit where the smallest element is removed and an NBC independent set is an independent set in I with no broken circuit. The set of NBC independent sets of any matroid M define a simplicial complex called the broken circuit complex which has been the subject of intense study in combinatorics. Recently, Adiprasito, Huh and Katz showed that the face of numbers of any broken circuit complex form a log-concave sequence, proving a long-standing conjecture of Rota. We study counting and optimization problems on NBC bases of a generic matroid. We find several fundamental differences with the independent set complex: for example, we show that it is NP-hard to find the max-weight NBC base of a matroid or that the convex hull of NBC bases of a matroid has edges of arbitrary large length. We also give evidence that the natural down-up walk on the space of NBC bases of a matroid may not mix rapidly by showing that for some family of matroids it is NP-hard to count the number of NBC bases after certain conditionings. 

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3. In-situ determination of the HfO2 -Ta2O5 -temperature phase diagram up to 3000°C

   https://doi.org/10.1111/jace.16271  

   McCormack, Scott J.; Tseng, Kuo-Pin; Weber, Richard J.; Kapush, Denys; Ushakov, Sergey V.; Navrotsky, Alexandra; Kriven, Waltraud M. (December 2018, Journal of the American Ceramic Society)

   The previously unknown experimental HfO2–Ta2O5‐temperature phase diagram has been elucidated up to 3000°C using a quadrupole lamp furnace and conical nozzle levitator system equipped with a CO2 laser, in conjunction with synchrotron X‐ray diffraction. These in‐situ techniques allowed the determination of the following: (a) liquidus, solidus, and invariant transformation temperatures as a function of composition from thermal arrest experiments, (b) determination of equilibrium phases through testing of reversibility via in‐situ X‐ray diffraction, and (c) molar volume measurements as a function of temperature for equilibrium phases. From these, an experimental HfO2–Ta2O5‐temperature phase diagram has been constructed which is consistent with the Gibbs Phase Rule. 

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4. The Naïve Bayes classifier++ for metagenomic taxonomic classification—query evaluation

   https://doi.org/10.1093/bioinformatics/btae743  

   Duan, Haozhe Neil; Hearne, Gavin; Polikar, Robi; Rosen, Gail L (December 2024, Bioinformatics)

   Kendziorski, Christina (Ed.)

   Abstract MotivationThis study examines the query performance of the NBC++ (Incremental Naive Bayes Classifier) program for variations in canonicality, k-mer size, databases, and input sample data size. We demonstrate that both NBC++ and Kraken2 are influenced by database depth, with macro measures improving as depth increases. However, fully capturing the diversity of life, especially viruses, remains a challenge. ResultsNBC++ can competitively profile the superkingdom content of metagenomic samples using a small training database. NBC++ spends less time training and can use a fraction of the memory than Kraken2 but at the cost of long querying time. Major NBC++ enhancements include accommodating canonical k-mer storage (leading to significant storage savings) and adaptable and optimized memory allocation that accelerates query analysis and enables the software to be run on nearly any system. Additionally, the output now includes log-likelihood values for each training genome, providing users with valuable confidence information. Availability and implementationSource code and Dockerfile are available at http://github.com/EESI/Naive_Bayes. 

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5. Preparation of CoGe ₂ -type NiSn ₂ at 10 GPa

   https://doi.org/10.1515/znb-2021-0115  

   Leineweber, Andreas; Wetzel, Marius Holger; Martin, Stefan; Shang, Shun-Li; Liu, Zi-Kui (September 2021, Zeitschrift für Naturforschung B)

   null (Ed.)

   Abstract An unprecedented NiSn 2 intermetallic with CoGe 2 -type crystal structure has been recovered (at ambient conditions) after high-pressure high-temperature treatment of a Ni 33 Sn 67 precursor alloy at 10 GPa and 400 °C. The orthorhombic structure with Aeam space group symmetry is pseudotetragonal. Based on the evaluation of powder X-ray diffraction data, lattice parameters of a  =  b  = 6.2818 Å and c  = 11.8960 Å have been determined. Complicated line broadening and results of a further microstructure analysis, however, imply a defective character of the crystal structure. First-principles calculations with different model structures and a comparison with structural trends in the literature suggest that at the high-pressure high-temperature conditions a CuAl 2 -type crystal structure might be stable, which transforms to the recovered CoGe 2 -type crystal structure upon cooling or the release of pressure. 

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