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An equal channel angular extrusion (ECAE) imposes severe plastic deformation into the workpiece to obtain ultrafine-grained materials. Since the strain level accumulated in materials during deformation history directly influences the grain size and distribution, the effect of ECAE process parameters on strain distribution was investigated using three-dimensional and non-isothermal finite element (FE) simulations depending on different processing routes and number of passes. The experimental data was utilized to identify the effect of accumulated mean strain values on yield and ultimate strengths of commercially available pure titanium (CP-Ti). Based on this, a design guideline to obtain desirable mechanical properties in the ECAE process to obtain uniform strain distribution or require minimum forming energy was proposed in the present investigation.

Finite element simulations are being widely used to increase the efficiency and effectiveness of design of bulk metal forming processes. In such simulations, proper consideration of friction condition is important in obtaining reliable results and the shear friction factor is widely used for bulk deformation for this purpose. In the earlier work for estimation of the shear friction factor, a radial tip was formed on the backward extruded end of the workpiece named ‘tip test’. It has been found that simple measurement of this radial tip distance from the external side surface of the deformed AL6061-O workpiece can be used to effectively determine the shear friction factor due to the linear relationship between the two. In the present investigation, the friction conditions at the punch and bottom die interfaces were determined based on finite element simulations. The shear friction factor at the bottom die was found to be about 60% of the one at the punch. The predicted shear friction factors compared well to the values obtained from the ring compression test.

The growth behavior of ZnO nanowires on an anisotropic crystalline substrate has been investigated in this work. On both the vicinal Si(1 0 0) substrate with a 6° miscut angle in the 0 1 1 Si direction and the on-axis Si(1 0 0) substrate, ZnO nanowires have been directly grown by thermal evaporation using the ball-milled ZnO powders under controlled conditions without the presence of catalyst. In this work, we confirmed that the vicinal surface of the substrate leads to selective growth during the initial growth of ZnO nanowires. For the vicinal substrate that consists of terraces separated by steps, ZnO nanowires are preferentially grown near step-edge lines aligned along the 0 1 1 Si azimuth. For the on-axis substrate, on the other hand, ZnO nanowires are randomly grown on the whole surface of the substrate. In addition, the average diameter of the nanowires grown on the vicinal substrate is slightly thinner than that of the nanowires grown on the on-axis substrate. The vapor–solid model is also proposed to explain the growth behavior of ZnO nanowires in our synthesis process.

The domain structure in epitaxial erbium silicide (ErSi 2 ) films grown on (1 0 0)Si substrates through the solid phase reaction during annealing is mainly investigated by X-ray diffraction methods. The ErSi 2 films grown on both the vicinal substrate and the on-axis substrate have a preferred orientation, i.e., the ( 1 1 0 0 ) plane of the ErSi 2 is parallel to the (1 0 0)Si surface, and the films consist of two types of domains, i.e., [0 0 0 1]ErSi 2 is parallel to either [0 1 1 ] Si or [0 1 1]Si. The ω -mode rocking curve measurements of the (2 2 0 1) ErSi 2 asymmetric reflection show that the volume fractions of two types of domains are almost equal on the on-axis surface and have a difference of about 30% on the vicinal surface. The formation of the double-domain structure is discussed on the basis of geometrical matching at interface between the (1 1 0 0) ErSi 2 film and the (1 0 0)Si substrate, and a growth model is also proposed.

Organochlorine (OC) and butyltin (BT) residues were detected in deep-sea and shallow water organisms collected from Suruga Bay, Japan. Among OCs, residue levels of polychlorinated biphenyls (PCBs) were highest in deep-sea organisms with up to 2800 ng/g lipid wt. Total butyltin (∑BT) concentrations in deep-sea organisms were found to be 980 ng/g wet wt. at maximum levels. Residue levels of OCs in both deep-sea and shallow water organisms from Suruga Bay were lower than those in industrialized areas like Tokyo Bay, whereas residue levels of BTs were comparable or higher. These facts clearly indicate the expansion of BT pollution in deep-sea ecosystems. The deep-sea organisms showed no consistent trend between OC concentrations and prey–predator relationships, while the accumulative pattern of BTs appeared to be influenced by food-chain magnification and feeding habits of the organisms. OC compositions in deep-sea organisms showed a higher ratio of p,p′-DDE, trans-nonachlor and β-HCH among their related compounds and isomers. Whereas TBT (tributyltin) as a parent compound of BT was predominant in deep-sea organisms, suggesting a fresh input of TBT into the deep-sea environment.

Organochlorine pesticides and polychlorinated biphenyls (PCBs) were determined in the blubber and liver of Steller sea lion collected from the bulk of Alaska and the Russian Bering Sea. PCBs were the predominant organochlorines in the blubber, ranging in concentration from 5.7 to 41 μg g−1 (lipid weight) in males and from 0.57 to 16 μg g−1 in females. Concentrations of DDTs (DDT and its metabolites) in the blubber ranged from 2.8 to 17 μg g−1 in males and from 0.19 to 6.5 μg g−1 in females. The levels of chlordane compounds (CHLs) and hexachlorocyclohexanes (HCHs) were one to three orders of magnitude lower than those of PCBs and DDTs. The residue levels of PCBs, DDTs and CHLs in males increased with age, whereas in females they decreased sharply after maturity, suggesting the transfer of organochlorines in large quantities during lactation. Transfer rate of organochlorines through lactation was estimated to be 80% for PCBs and 79% for DDTs of the total body of adult female. Concentrations of organochlorines in the liver of the Steller sea lion from Alaska, on a lipid weight basis, were similar to those in the blubber. In addition, liver showed age-dependent accumulation of PCBs, DDTs and CHLs, similar to that in the blubber. The concentrations of all the organochlorines detected in the liver were clearly correlated with those in the blubber, indicating the lipophilic nature of organochlorines in accumulation and movement in the animal body. Residue levels of PCBs and DDTs in the liver of male Steller sea lions from the Bering Sea were significantly lower than those from Alaska, suggesting that Bering Sea animals have different foraging areas from the animals of the bulk of Alaska.

The present study was conducted to elucidate the specific distribution of butyltin (BT) compounds in various tissues and organs of Steller sea lions collected from coastal waters of Hokkaido, Japan. BT concentrations were an order of magnitude higher in the liver than in other tissues and organs except hair, whereas organochlorine (OC) compounds accumulated at two to three orders of magnitude higher in blubber than in other tissues. No relationship was observed between BT concentrations and the lipid content in tissues, while the levels of OCs were positively associated with the lipid content. The levels of BTs in hair (1500 ng g−1 on a wet weight basis) were the highest of all the tissues analysed. Results also suggested that 26% of the total BT burden in the body was eliminated through shedding. Selective accumulation of BTs in liver and hair is attributed to its protein-binding capacity rather than lipophilicity. The discovery of high concentrations of BTs in hair implies their excretion by shedding in piliferous animals.