Genome sequences of actinobacteriophages JorRay, Blocker23, Nibbles, and OlgasClover.

JorRay, Blocker23, Nibbles, and OlgasClover are actinobacteriophages belonging to clusters G1, B2, CT, and DJ, respectively. JorRay and Blocker23 were identified in host bacterium Mycobacterium smegmatis mc2155. Nibbles and OlgasClover were identified in host bacterium Gordonia rubripertincta NRRL B-16540.

Reduction in Processing Time in Ca3Co4O9+δ Ceramics through Nanoprecursors Produced by an Easily Scalable and Environmentally Friendly Process.

Attrition milling is an easily scalable and environmentally friendly process used to produce Ca3Co4O9+δ nanoprecursors in a relatively short time. Sintered materials produced through the classical solid-state method, involving ball milling, show much larger grain sizes and slightly lower density than those obtained in samples produced from attrition-milled precursors. On the other hand, electrical resistivity has been drastically decreased, accompanied with a slight decrease in the Seebeck coefficient in samples obtained from these attrition-milled precursors. Moreover, the use of an attrition milling process leads to a very important reduction in processing time (around 75%), together with a slight power factor improvement of around 10%, when compared to the classically prepared samples.

Influence of Ag on the Properties of Ca0.9Yb0.1MnO3 Sintered Ceramics.

In this study, Ca0.9Yb0.1MnO3 + x wt.% Ag (with x = 0, 1, 3, 5, and 10) thermoelectric materials were prepared via the classical ceramic method. In spite of the very high sintering temperature (1300 °C), no significant Ag losses were observed following this process. Moreover, Ag addition enhanced cation mobility during sintering due to the formation of a liquid phase. Microstructurally, it was found that Ag decreases porosity; this was confirmed by density measurements. Ag was also found to promote the formation of a Ca2Mn2O5 secondary phase. Despite the presence of this secondary phase, samples with Ag displayed lower electrical resistivity than Ag-free ones, without a drastic decrease in the absolute Seebeck coefficient. The highest thermoelectric performances, which were determined by power factor, were obtained in 1 wt.% Ag samples. These maximum values are slightly higher than the best of those reported in the literature for sintered materials with similar compositions, with the additional advantage of their being obtained using a much shorter sintering procedure.

Right Heterogeneous Microstructure for Achieving Excellent Thermoelectric Performance in Ca0.9R0.1MnO3-δ (R = Dy, Yb) Ceramics.

Perovskite manganite Ca0.9R0.1MnO3-δ (R = Dy, Yb) ceramics have been synthesized by a traditional solid-state reaction with multicalcination processes. A heterogeneous microstructure including large and small micrometer-sized grains, coherent interfaces, and oxygen defects has been formed with optimized calcination time. The carrier concentration of the third-calcined samples is enhanced approximately 3 times compared with those synthesized through conventional methods. Thus, the electrical resistivity of the third-calcined Ca0.9R0.1MnO3-δ (R = Dy, Yb) ceramic samples obviously decreases, leading to a higher power factor. Additionally, the thermal conductivity is also reduced by multiscale scattering of the heterogeneous structure. The lowest lattice thermal conductivities of Dy- or Yb-doped samples are 1.24 and 1.22 W m-1 K-1, respectively. Thus, the high thermoelectric performance for Ca0.9R0.1MnO3-δ (R = Dy, Yb) has been achieved by the multicalcination process. The highest figure of merit is almost 30% higher than that of the first-calcined samples. Therefore, a heterogeneous microstructure formed by optimized multicalcination can effectively optimize the thermoelectric performance of oxides.

Long-Term High-Temperature Stability of Directionally Grown [Bi2Ba2O4]p[CoO2] Rods.

[Bi2Ba2O4]p[CoO2] thermoelectric ceramics have been successfully grown from the melt using the laser floating zone method, followed by a thermal treatment at 700 °C under air between 0 and 1532 h. The microstructural, thermoelectric, and mechanical properties were evaluated as a function of the thermal treatment length. Microstructure has shown that as-grown samples are composed of thermoelectric grains, together with a relatively high amount of secondary phases. Thermal treatment decreased the number and amount of secondary phases, producing nearly single-phase samples after 384 h. Consequently, the thermoelectric properties evaluated through the power factor showed a slight increase with the thermal treatment length, mainly due to the decrease of electrical resistivity, while the Seebeck coefficient was nearly unchanged. On the other hand, flexural strength was practically constant after 24 h thermal treatment.