Investigation of Effect of Preliminary Annealing on Superplasticity of Ultrafine-Grained Conductor Aluminum Alloys Al-0.5%Mg-Sc

Effect of preliminary precipitation of Al3Sc particles on the characteristics of superplastic conductor Al-0.5%Mg-X%Sc (X = 0.2, 0.3, 0.4, 0.5 wt.%) alloys with ultrafine-grained (UFG) microstructure has been studied. The precipitation of the Al3Sc particles took place during long-time annealing of the alloys at 300 °C. The preliminary annealing was shown to affect the superplasticity characteristics of the UFG Al-0.5%Mg-X%Sc alloys (the elongation to failure, yield stress, dynamic grain growth rate) weakly but to promote more intensive pore formation and to reduce the volume fraction of the recrystallized microstructure in the deformed and non-deformed parts of the aluminum alloy specimens. The dynamic grain growth was shown to go in the deformed specimen material nonuniformly–the maximum volume fraction of the recrystallized microstructure was observed in the regions of the localization of plastic deformation.

Evaluation and consideration of local specimen material properties in lifetime prediction of short fibre reinforced PA6T/6I

To exploit the full material potential of short fibre reinforced PA6T/6I, specific component calculations including aniso- tropic material behaviour is necessary. For this, different failure criteria and fatigue models are used to describe the behaviour during a component service life. This paper deals with the determination and consideration of fibre orientations for failure criteria and fatigue calculations. Therefore, a novel method to determine fibre orientation (FO) distributions across injection moulded plates, is proposed. The developed method allows a forecast of FOs for different specimen extraction positions and angles on injection moulded plates by using only a few measured reference points. As a result, fatigue models can be calibrated with the strength values and the corresponding FO, calculated for fracture position. The performed tests show a non-negligible influence of failure positions, due to fibre orientation distributions along the specimens. So, the FO determination method delivers an improvement in strength values estimation.

Development of comparative investigation method for timing chain wear analysis using oscillating tribometer

This paper presents the development of a test procedure to investigate timing chain components under abrasive stress on a tribometer. Engine developers use cost and time expensive engine dynamometer tests to investigate timing chain life expectancy under different conditions. Tribometer tests are fast and cost effective, but these use standardized specimen material and geometry that greatly differ from the original tribological system of the timing chain. Manufacturing specimens from the original chain material using the original technology is complicated; surface quality and hardness properties cannot be guaranteed. The aim of research was to develop a test method for rapid and cost-effective comparison of engine lubricants, timing chain materials or coatings, as well as to assess the wear resistance of the chain to contaminants. Various uncontaminated and carbon black blended lubricants were compared using standard-based ball-on-disc tribometer tests to tribometer tests using actual timing chain components (bush-on-pin test) of a Diesel engine. Lubricants were ranked in terms of coefficient of friction and wear. Results showed that bush-on-pin tests were comparably suitable for testing lubricants when evaluated against standard ball-on-disc tribometer tests.

Effects of TiO2 nanoparticle lubricant on micro deep drawing performance

Micro deep drawing is a process to manufacture the thin walled, hollow, box or cup like products at micro scale. Lubricant can affect the products’ quality in micro deep drawing at micro scale due to the decrease of coefficient of friction between the material and tools, it is crucial to enhance the forming efficiency. In this study, 40 µm thickness stainless steel 301 (SUS301) was annealed at 980 ℃ for 2 min under protection of argon gas ambient, and this stainless steel was selected as the specimen material. The micro deep drawing was conducted on a micro press machine under dry and 4% TiO2 nanoparticle lubrication conditions with different forming velocities. The experimental results showed that the micro cup’s profile is affected by changing the forming velocity under the dry and nanoparticle lubrication conditions. Under the dry condition, the surface became rough with the increase of the forming velocity, and then the micro forming efficiency under application of nanoparticle lubricant increases with a rise of drawing velocity.

The phylogenetic position and taxonomic status of the Southeast and South Asian bamboo genera Neohouzeaua and Ochlandra (Poaceae: Bambusoideae)

Among the tropical woody bamboos, the Melocanninae is one of the most clearly recognized subtribes morphologically and has also been consistently well delimited in molecular phylogenetic work. The relationships among those genera in this subtribe, however, have been contentious because of poorly understood generic delimitations, in part due to poor specimen material or insufficiently assessed morphological traits, sometimes exacerbated by poorly accessible provenances. We address the phylogenetic and taxonomic status of two groups which together include the largest number of species in this subtribe: the Neohouzeaua-Schizostachyum complex, distributed from India to South China, Southeast Asia and southwest Pacific, and the endemic Indian genus Ochlandra. Three Neohouzeaua species (including the generic type), 12 Schizostachyum species (including the generic type and several species of uncertain placement), together with five species of Ochlandra and representatives of Cephalostachyum, Melocanna and Pseudostachyum were assessed in a molecular phylogenetic analysis together with members of other well-distinguished subtribes. Members of Neohouzeaua and Schizostachyum align into two main groups that were not completely well-supported statistically but which members possess mostly reflexed culm leaf blades, or mostly erect culm leaf blades. Other characters which provide obvious differences between taxa, such as the number of flowers in a pseudospikelet, fusion of filaments into a staminal tube, and presence of lodicules, were inconsistent between these groups. Neohouzeaua and Schizostachyum cannot be clearly distinguished in either morphological or molecular terms, and thus are united under the latter name, which takes precedence. In reviewing names in Neohouzeaua and their basionyms, several lectotypifications are designated. Three new combinations in Schizostachyum are proposed. On the other hand, Ochlandra forms a distinct clade and its monophyly is demonstrated, supported by clear morphological characters.

Optimization of Novel Sphere Sandwich Structure for Impact Requirements

Sphere Sandwich Structures (SSS) are a new structure which may have the potentials to provide the energy absorption as compared with monolithic specimen material. By using innovation carving wax method, fifteen specimens have been prepared according to RSM optimize method and it machined by CNC-3axis machine with sphere end screw. Three factors sphere diameter(D), distance between spheres(X) and skin thickness(K) have been studied. The impact test has been achieved by Izod test to calculate specific fracture toughness. The results show the sample 642 has the highest specific fracture toughness value with an improvement of 300% compared with the monolithic sample. The optimal value of this test is 35.37 MPa m0.5 g-1 of the sample 682 (diameter = 6, distance between spheres = 8, skin thickness = 2 mm) with 10% error when compared with practice result at the same geometry. According to ANOVA analysis, the diameter of sphere(D) has greatest effect than other factors and then skin thickness(K).

RECENT ORNITHOLOGICAL EXPEDITIONS TO SIBERUT ISLAND, MT. TALAMAU AND RIMBO PANTI NATURE RESERVE, SUMATRA, INDONESIA

Siberut Island, Mt. Talamau, Rimbo Panti Nature Reserve, and intervening locations in West Sumatra Province were visited during two expeditions in 2018-2019 by ornithologists from the Museum Zoologicum Bogoriense (MZB) - Indonesian Institute of Sciences (LIPI), Louisiana State University Museum of Natural Science (LSUMNS), and Andalas University. The main objective of these expeditions was to obtain data and tissue-subsample rich museum specimens for morphological and genetic studies of phylogeny and population genetics of Southeast Asian birds aimed at understanding the causes of avian diversification in the region. We also observed, photographed, and audio-recorded numerous bird species during the expeditions and archived these data. In total, 285 species were identified, and specimen material was collected from 13 species and 26 subspecies not previously represented in tissue resource collections. Here, we provide complete lists of birds found at each location, highlight distributional discoveries, and note cases of potential taxonomic, ecological, and conservation interest.

TO STUDY MECHANICAL PROPERTIES OF SPRING LIKE SPECIMEN BEFORE AND AFTER DIFFERENT HEAT TREATMENT OPERATIONS

In this work we have analyzed the effect heat treatment on properties of spring shape steel specimens under various heat treatment processes. Specimen was subjected to heat treatment in electric muffle furnace. Heat treatment temperature, soaking time and cooling rate were selected as per phase diagram of specimen material. Specimen was tested for mechanical properties before and after heat treatment. Two processes annealing and normalizing compared with respect to their effect on properties of spring shape specimens in reference with standard data for steel used.

New seriated Amathia species in Japan, with a redescription of A. acervata Lamouroux, 1824 (Bryozoa: Ctenostomata)

The status of seriated Amathia species (Bryozoa: Ctenostomata) in Japan is reviewed. Several historical specimens and materials recently collected from several localities along the Japanese coast are examined in this study. Amathia acervata Lamouroux, 1824, collected from Japan by Wilhelm Gottlieb Tilesius in 1804, was examined and is redescribed from a reconstituted fragment of the sole type specimen. Material previously reported from Wakayama Prefecture is very similar to Amathia acervata, but differs in having fewer autozooid pairs per cluster, which spiral in different directions; the species is described as a new species Amathia brevisilva n. sp. Measurements of colony characters vary according to the effects of fixation, but stolon length, the ratio of autozooid clusters on stolons, spirality and pigmentation are useful characters for the identification of Japanese seriated Amathia. In addition, two new species are described, Amathia reptopinnata n. sp. and Amathia fimbria n. sp. Amathia reptopinnata n. sp. is characterized by its robust form, dark colour, dichotomous branching, long stolons, long autozooidal clusters and pinnately arranged prostrate zooids. Amathia fimbria n. sp. was found only in the Showa Emperor collection, and is characterized by its compact colony form, remarkably short internode length and trichotomous branching.