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In this study, the synergistic effects of a hybrid surface treatment involving hydrochloric acid (HCl) immersion and silanization on friction stir spot welding (FSSW) of aluminum and carbon fiber reinforced thermoplastic (CFRTP) were investigated. Maximum tensile shear strength of 10.2 kN and maximum cross-tension strength of 1.92 kN were achieved. An unloading test and a miniature tensile test revealed that the fracture behavior changed from interfacial to CFRTP fracture due to increased interfacial strength with the hybrid treatment and utilization of the CFRTP strength enhanced the joint strength. The nanostructures at the interface with HCl immersion treatment indicated that the interfacial properties were improved mechanically in addition to the chemical enhancement by silanization. Owing to the hybrid treatment, aluminum and CFRTP were efficiently joined by the adhesion behavior of spreading melted plastic resin during the FSSW process.

This study identified the work-hardening parameters and fracture strain of a hardened die-steel (SKD11). Herein, a shear punching test was used as the low stress-triaxiality suppresses material fracture due to the brittle behavior of SKD11 in tensile tests. Furthermore, a minute punch-die clearance was used to increase the compression stress due to the material deformation. SKD11 steel sheets of 1.0 mm thickness were successfully deformed, and the punching force as well as stroke were recorded for inverse analysis using the finite element analysis (FEA). Subsequently, FEA of the shear punching test was repeated to optimize the parameters of Swift’s work-hardening law. Consequently, the Swift parameters were derived to ensure that the measured values of the punching force and stroke correspond with the numerically simulated curve. The fracture strain was identified as the maximum equivalent plastic strain at the punch stroke of specimen rupture.

This study assesses the applicability of the Weibull stress for the assessment of the crack-tip plastic constraint effect as well as the mixed mode I and II loading effect on brittle fracture resistance of a ferritic steel. Brittle fracture toughness under different crack-tip plastic constraint conditions and different loading mode conditions was respectively obtained by conducting 3-point bend (3 PB) test for single edge cracked specimens with different crack depth subjected to mode I load, and 4-point shear (4 PS) test for a single edge cracked specimen with deep crack depth subjected to mixed mode I and II load. By using the results of 3 PB tests, the critical Weibull stresses distribution independent of crack-tip plastic constraint was identified, and the critical Weibull stresses obtained by 4 PS tests provided significantly smaller distribution than that for 3 PB specimen. The mixed mode loading provides the different combined stress field around the crack-tip from that under mode I loading, where the 4 PS specimen showed the lower distribution of σ2/σ1 and σ3/σ1 than the 3 PB specimens. The lower principal stress ratio to be enlarge the fracture driving force was found to have no or much less influence to linear energy release rate for micro-crack, that was employed in the conventional derivation of the Weibull stress. Consequently, the reason why the conventional Weibull stress could not evaluate the effect of loading mode on fracture resistance could be that the linear energy release rate could not exactly take into account the local fracture driving force enlarged due to the combined stress field under mixed mode loading.

This paper evaluates fracture strains of two types of 590 MPa-class steel sheets, JSC590Y and JSC590R with the thickness of 1.2 mm. Small circular-rod specimens with the minimum diameter of 1.0 mm in the gauge region were tensioned under hydrostatic pressures of 200 and 400 MPa for this evaluation. Time histories of minimum diameter were measured and then converted to true strain histories. The tensile tests revealed different fracture strain behavior due to hydrostatic pressures in the two steel sheets: JSC590R showed an increase in fracture strains at high hydrostatic pressures, but JSC590Y presented almost consistent fracture strains for all tested pressures.

Microstructures in the liver are primarily composed of hepatocytes, hepatic blood, and biliary vessels. Because each hepatocyte comes in contact with both vessels, these vessels form three-dimensional (3D) periodic network patterns. Confocal microscope images are useful for observing 3D structures; however, it is necessary to explicitly describe the vessel structures using 3D images of sinusoidal endothelial cells. For this purpose, we propose a new approach for image segmentation based on the Turing reaction-diffusion model, in which temporal and spatial patterns are self-organized. Turing conditions provided reliable tools for describing the 3D structures. Moreover, using the proposed method, the sinusoidal patterns of rats fed a high-fat/high-cholesterol diet were examined; these rats exhibited pathological features similar to those of human patients with nonalcoholic steatohepatitis related to metabolic syndrome. The findings showed that the parameter in diffusion terms differed significantly among the experimental groups. This observation provided a heuristic argument for parameter selection leading to pattern recognition problems in diseased rats.

本研究は，奈良マラソン2014の参加者を対象に，ランナーの居住地域別にデスティネーションイメージの相違を明らかにすることを目的とした．奈良マラソン2014終了後, 参加ランナーに調査の協力依頼をし，インターネット調査を実施した．郵便番号で回答者の居住地（都道府県）を特定することにより「近畿地方以外」と「近畿地方」の2グループに分けた．ランナーの居住地を独立変数とし，デスティネーションイメージを従属変数としてt検定による平均値の差を分析した．結果としては，近畿地方以外から来たランナーは,近畿地方のランナーよりも，8つの項目の得点が高くなったのに対し，2つの項目の得点が低くなった．近畿地方以外から来たランナーにとって，奈良に対する良いイメージは，文化，都市観光と利便性であることが明らかとなった．, The purpose of this study was to clarify the differences in destination image among the Nara Marathon 2014 runners who came from different residential areas. After the completion of the Nara Marathon 2014, we conducted an internet survey on the runners who participated. By distinguishing the respondents' places of residence (prefecture) by zip code, respondents were divided into two groups, "outside the Kinki region" and "Kinki region." We analyzed the difference in mean value by a t-test using the runners' place of residence as an independent variable, and destination image as a dependent variable. Results revealed that the group "outside the Kinki region" scored higher on eight items. Meanwhile, they scored lower on two items. Thus we concluded that runners who came from outside the Kinki region, considered Nara an excellent place for "culture," "urban sightseeing," and "convenience.", 原著(Original investigation)

本研究の目的は、奈良マラソン2016ランナーを対象に調査を行い、その結果からスポーツ参加者の行動様式を明らかにすることである。調査項目は、個人属性、ランニング活動、大会参加状況と満足度、宿泊、消費支出、奈良マラソンについての要望、総合的な評価と次大会への参加である。以上の項目について単純集計、または性別および年代によるクロス集計を行い、考察を加えてリサーチレポートを作成した。調査の結果として、性別や年代のほか、ランニングへの取り組みなど、参加者の実態を把握することができた。, The purpose of this study was to clarify runners' behavioral patterns based on an analysis of the sports event. The research items include (i) individual attributes; (ii) running activities; (iii) marathon participation and event satisfaction; (iv) residential information; (v) consumption expenditure; (vi) demand for the Nara Marathon; (vii) comprehensive evaluation and intention to revisit. Our analysis included a simple and cross tabulation by sex and age. The result of analysis clarified runners' aspect such as sex, age, and running activities., 報告(Report)

本研究の目的は，奈良マラソン2014参加者の居住地に着目し，マラソン参加に伴う消費支出の傾向を明らかにすることである．分析にあたっては，居住地を独立変数とし，消費支出額を従属変数とした一元配置の分散分析及び多重比較検定を行った．分析の結果，交通費，宿泊費，飲食費，日用品費・食品費，観光娯楽費，土産代，EXPO支出額の7項目で，居住地が奈良県から遠くなるほど消費支出額も高くなる傾向がみられた．, The purpose of this study was to clarify the runner's tendency of a consumption expenditure based on prefectures in which they live. In this analysis, the dependent variable is the place of residence and independent variables are the price of consumption expenditure. Our analysis of variance and multiple comparison tests show that participants who live far from Nara prefecture tend to spend higher expenses on the following: traveling, lodging, meals, commodities and foods, sightseeing and amusement, souvenirs, EXPO expenses., 原著(Original investigation)

Open-field tests are routinely used to study locomotor activity in rodents. I studied the effects of apparatus size on rodent locomotor activity, specifically with respect to how resting and walking periods are interwoven. I explored the open-field behavior of mice utilizing circular open fields of various diameters. When the diameter of the test apparatus was greater than 75 cm, the durations of the resting and moving periods of free walking behavior obeyed bounded power-law distribution functions. I found that the properties of the scaling exponents and model selection became similar for test apparatus diameters greater than 75 cm. These results can provide a guide for the selection of the size of the test apparatus for use in the study of the open-field behavior of rodents.

The strength of a dissimilar joint between aluminum and steel is generally dependent on the thickness of the intermetallic compound (IMC) layer. Mechanical factors such as the residual stress and stress field under loading also likely contribute to the fracture behavior of the joint. However, a clear understanding of the effects of the interfacial structure (i.e., the IMC layer thickness) and mechanical factors on joint strength is lacking in the existing literature. The purpose of this study was to elucidate the influence of both the IMC layer thickness and the difference in the strengths of dissimilar metals on the interfacial strength of aluminum/steel joints through experimental evaluations and finite element (FE) analyses. The relationship between the strength of a friction-stir-welded joint of 6061 aluminum alloy (A6061) and 780-MPa grade high-tensile-strength steel (HT780) and the IMC layer thickness was investigated by controlling the IMC growth promoted by the annealing process. The results showed that the joint strength decreased with increasing IMC layer thickness. Fracture mainly occurred at the joint interface for a thin IMC layer of approximately 100 nm, whereas the joint between A6061 and 304 stainless steel, with a lower proof stress than HT780, showed a higher joint strength that resulted in fracture in the A6061 alloy. The FE analysis revealed that a high maximum principal stress is applied near the interface due to the difference in the degree of deformation between steel and aluminum, a behavior that is likely to appear in any joint consisting of materials with considerably different strengths.

Dissimilar joints generally involve the formation of a non-uniform interfacial reaction layer, which affects the joint strength significantly. However, a clear understanding of the effect of interfacial local strength on the macroscopic fracture behavior of the dissimilar joints is lacking in the existing literature. Here, we demonstrate the influence of interfacial reaction layer on the fracture behavior of the friction stir spot welded dissimilar joints between galvanized steel and aluminum alloy through the microscale evaluation of interfacial strength in addition to the conventional macroscale evaluations. Macroscale evaluations showed that the rim region of the joint, which includes a thin reaction layer comprising of both intermetallic compound (IMC) with several hundred nm thickness and Zn-concentrated area partly including voids derived from the discharge of galvanized layer, primarily resists the fracture in tensile shear and cross tension tests. Microscale cantilever beam bending tests showed that the interfacial strength increases with the decrease of reaction layer thickness except in the case of voids. Our study highlights the significance of rim region in spot welding, which has been indicated only by macroscale evaluations.

The purpose of this study is to propose a method to correlate micro-structural characteristics of two-phase steel with structural performance in terms of ductile crack growth resistance (R-curve). For this purpose, a meso-scopic simulation method is proposed to predict two types of ductile properties of two-phase steel that control the R-curve from micro-structural characteristics. The R-curve of three-point bend specimen with fatigue pre-crack predicted by a macro-scopic simulation method that we have proposed, in which these two types of ductile properties obtained by the proposed meso-scopic methods are implemented, is in good agreement with experimental result.

An evaluation of Charpy impact toughness of the weld metal for laser beam welds is often impossible due to occurrence of fracture path deviation (FPD) from the weld metal into base steel. Therefore, the improved toughness evaluation method using side-grooved specimen instead of normal specimen has been suggested for preventing FPD. However, for a pre-qualification of the toughness of laser welds, the toughness value obtained with side-grooved specimen should be corrected to the toughness value of normal Charpy specimen. In this study, the method for correction of side-grooved Charpy energy for laser welds to normal Charpy impact toughness suggested by Hagihara et al. (Q J Jpn Weld Soc 25: 165–172, 2007) is advanced by means of FE analysis with focus on the deformation behaviors associated with strength mismatch. Furthermore, the distinctive strength mismatch of laser welds on lateral contraction of Charpy specimen has been analyzed by means of the Weibull stress approach. The applicability of the advanced engineering method is demonstrated by comparing experimental result, whereas the further verification should be accumulated.