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A two-dimensional unsteady numerical simulation with a detailed chemical reaction mechanism that considers 158 species and 1804 reactions is applied to pulverized coal combustion in a mixing layer and the soot formation behavior is investigated in detail. The computational conditions and ignition process are the same as those in our previous work (Muto et al., 2017). The results show that the peak of the mass density of the soot is distributed in the region where the gas temperature is higher than the unburned gas temperature of the mixture of volatile matter and air (1300–1400 K) and lower than the flame temperature (2000 K ∼ ). This is due to the fact that soot formation from the precursors (C2H2 and C6H6) is enhanced as the gas temperature increases, whereas the quantities of the precursors and the produced soot are reduced due to oxidation at the higher gas temperature condition that exists close to the flame. The peak value of the mass density of the soot is also distributed in the region between the peak values of the gas temperature and the probability density function of the number of coal particles.

A large-scale machine tool is typically very inefficient in size, cost, and energy consumption. Some large parts only have a set of machining features, each of which is within a small local region, and their location should meet position and orientation tolerances. In such a machining application, as a more cost- and energy-effective alternative, this paper presents the concept of a “portable” machine tool, where a small machining platform, with the capability to machine each local machining feature in the required accuracy, is moved by long coarse linear axes. The coarse axes only perform the point-to-point positioning to each machining feature and fixed by servo control during the machining. They do not have sufficient positioning repeatability. To ensure the position/orientation accuracy of each machining feature without having highly repeatable coarse axes, this paper proposes the application of a tracking interferometer to measure all the error motions of coarse axes, and then to perform their compensation. This can be seen as a closed-loop feedback control for coarse axes using the tracking interferometer in the loop. The proposed concept is demonstrated by the experiments with its prototype using a six-degrees of freedom robot moved by two coarse linear axes.

A two-dimensional direct numerical simulation with a detailed chemical reaction mechanism that considers 158 species and 1804 reactions is applied to pulverized coal combustion occurring in a mixing layer and the ignition phenomena is investigated in detail. The pulverized coal particles which are initially heated up to 2000 K are distributed in a fully developed mixing layer. The distributions of temperature and various chemical species concentrations in terms of the mixture fraction are analyzed during ignition. The results show that the ignition occurs in the rich mixture fraction condition ( ξ ∼ 0.2 ), as the gas temperature is also high in this condition because of the high initial temperature set for the central coal particles. However, once ignition occurs, the combustion reaction dramatically takes place in the condition indicating ξ = 0.03–0.06, which is a slightly lean value compared with the stoichiometric value and shows the shortest ignition delay time in the calculation for autoignition of homogeneous mixtures of volatile matter and air (zero-dimensional calculation). In addition, in the combustion reaction zone, high OH radical mass fraction is observed around the conditions of stoichiometric mixture fraction, whereas high CH radical mass fraction is observed in the rich mixture fraction conditions.

The morphological similarity between upstream fatminnow Rhynchocypris oxycephalus and downstream fatminnow Rhynchocypris lagowskii makes it difficult to discriminate accurately between these species in rivers where they coexist. For easy and precise identification of these two species, we developed a genetic discrimination method based on PCR-RFLP analysis for specimens from the Inohzawa River watershed in the Izu Peninsula, central Honshu, Japan. This genetic method was applied to the species identification of the fatminnows from two other watersheds, the Kano and Kawazu Rivers, flowing across the peninsula from north to south. We present the genetic evidence for the restricted distribution of R. oxycephalus and the ubiquitous distribution of R. lagowskii in the peninsula.

Scombrops gilberti is a member of the percoid family Scombropidae, which includes a single genus and three to four species worldwide. Little is known about the ecology of this species. Juvenile S. gilberti have been found in the waters off northern Japan (Iwate Prefecture), whereas adults are found in the waters around the southern counterpart (Izu Islands), approximately 700 km from the northern waters. In the present study, we captured immature S. gilberti (106–248 mm standard length, SL) in the northern waters by set net at 8–80 m depth, whereas larger individuals (150–328 mm SL) were captured by trawling at 150–500 m depth. By contrast, only adult S. gilberti (422–590 mm SL) were captured in the southern waters. The genetic composition of the adult population of S. gilberti from the southern waters and of the juvenile population from the northern waters was compared using the nucleotide sequence of the mitochondrial DNA (mtDNA) cytochrome b gene. No significant differences in genetic parameters such as fixation index, neutrality test or mismatch distribution analysis were found between these geographically distinct populations of S. gilberti, showing that these populations are genetically homogeneous.

Two scombropid fishes, Scombrops boops and Scombrops gilberti, are closely related and commercially important species in Japan. These species are often confused in commercial markets because of their morphological similarity. In this study, scombropid specimens collected from various Japanese coastal waters were subjected to polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis and phylogenetic analysis of the 16S rRNA gene in mitochondrial DNA. These analyses showed that all the scombropid specimens collected from localities in the Sea of Japan were identified as S. boops, whereas those from the Pacific Ocean included two species, S. boops and S. gilberti. Almost all juvenile (200 mm standard body length, S(L)) S. gilberti originated from the Pacific coastal waters of the northern Japan, whereas adults (400 mm S(L)) were found only in deep water off the Izu Peninsula to the Izu Islands. This suggests that S. gilberti might migrate extensively during its life cycle. In addition, differences in the number of specimens and the distribution between the two species suggest that S. gilberti is less abundant than S. boops in Japanese waters.

Aims: We compared phenotypic characteristics of Lactococcus lactis subsp. lactis derived from different sources including the intestinal tract of marine fish and freshwater fish, and cheese starter culture. Methods and Results: In the phylogenetic analysis based on partial 16S rRNA gene nucleotide sequences (1371 bp), freshwater fish-, marine fish- and cheese starter culture-derived strains were identical to that of L. lactis subsp. lactis previously reported. Fermentation profiles determined using the API 50 CH system were similar except for fermentation of several sugars including l-arabinose, mannitol, amygdalin, saccharose, trehalose, inulin and gluconate. The strains did have distinct levels of halotolerance: marine fish-derived strains > cheese starter-derived strain > freshwater fish-derived isolate. Conclusions: Lactococcus lactis subsp. lactis showed extensive diversity in phenotypic adaptation to various environments. The phenotypic properties of these strains suggested that L. lactis subsp. lactis strains from fish intestine have additional functions compared with the cheese starter-derived strain that has previously described. Significance and Impact of the Study: The unique phenotypic traits of the fish intestinal tract-derived L. lactis subsp. lactis might make them useful as a probiotics in aquaculture, and contribute to the development of functional foods and novel food additives, since the strains derived from fish intestines might have additional functions such as antibacterial activity.