ABSTRACT
Characterization of very high cycle fatigue (VHCF) performance is of significant issue for ensuring long‐term durability and reliability of machinery and structural components due to the ...growing industrial demands and significant requirements of the advanced systems. In this study, VHCF characteristics of nanocrystallized skins (nanoskin) on JIS SCM435 (AISI 4137) steels were investigated as three different nanoskins on the surface, which was fabricated by altering the static load of ultrasonic nanocrystal surface modification (UNSM) treatment. The fatigue characterization, which shows linearly proportional correlation in the range of 80–120 µm depth of subsurface, was subjected to severe plastic deformation by altering the static loads of UNSM treatment to 40, 70 and 100 N, respectively. The fatigue strength increased up to 30% in the regime of VHCF. The improved strength mainly resulted from the generation of nanocrystalline structure, the enhanced surface uniformity, hardness and residual stress.
ABSTRACT
A series of axial tensile fatigue tests (R = 0.1) was carried out to investigate the initiation and the growth behaviours of very small surface fatigue cracks under two different surface ...conditions (viz. smooth and pitted surfaces) of AISI 304 stainless steel at room temperature. This paper deals with both of the two approaches regarding the analysis of fatigue: the approach based on the concept of fracture mechanics and low cycle fatigue. In particular, both the initiation and growth of cracks and the coalescence of small cracks by fatigue in the specimen have been investigated by the methods of surface replicas and photomicrographs. Quantitative information such as the initiation period, growth and coalescence behaviours of small cracks, and crack growth properties were systematically obtained. The results show that the accurate determination of these parameters is critical for the application of fracture mechanics to fatigue life assessment.
In this paper, the prediction skills of five ensemble methods for temperature and precipitation are discussed by considering 20 yr of simulation results (from 1989 to 2008) for four regional climate ...models (RCMs) driven by NCEP–Department of Energy and ECMWF Interim Re-Analysis (ERA-Interim) boundary conditions. The simulation domain is the Coordinated Regional Downscaling Experiment (CORDEX) for East Asia, and the number of grid points is 197 × 233 with a 50-km horizontal resolution. Three new performance-based ensemble averaging (PEA) methods are developed in this study using 1) bias, root-mean-square errors (RMSEs) and absolute correlation (PEA_BRC), RMSE and absolute correlation (PEA_RAC), and RMSE and original correlation (PEA_ROC). The other two ensemble methods are equal-weighted averaging (EWA) and multivariate linear regression (Mul_Reg). To derive the weighting coefficients and cross validate the prediction skills of the five ensemble methods, the authors considered 15-yr and 5-yr data, respectively, from the 20-yr simulation data. Among the five ensemble methods, the Mul_Reg (EWA) method shows the best (worst) skill during the training period. The PEA_RAC and PEA_ROC methods show skills that are similar to those of Mul_Reg during the training period. However, the skills and stabilities of Mul_Reg were drastically reduced when this method was applied to the prediction period. But, the skills and stabilities of PEA_RAC were only slightly reduced in this case. As a result, PEA_RAC shows the best skill, irrespective of the seasons and variables, during the prediction period. This result confirms that the new ensemble method developed in this study, PEA_RAC, can be used for the prediction of regional climate.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Display omitted
Through-silicon via (TSV) has been used for 3-dimentional integrated circuits. Mechanical stresses in Cu and Si around the TSV were measured using synchrotron X-ray microdiffraction. ...The hydrostatic stress in Cu TSV went from high tensile of 234MPa in the as-fabricated state, to −196MPa (compressive) during thermal annealing (in situ measurement), to 167MPa in the post-annealed state. Due to this stress, the keep-away distance in Si was determined to be about 17μm. Our results suggest that Cu stress may lead to reliability as well as integration issues, while Si stress may lead to device performance concerns.
Why People Are in a Generally Good Mood Diener, Ed; Kanazawa, Satoshi; Suh, Eunkook M. ...
Personality and social psychology review,
08/2015, Letnik:
19, Številka:
3
Journal Article
Evidence shows that people feel mild positive moods when no strong emotional events are occurring, a phenomenon known as positive mood offset. We offer an evolutionary explanation of this ...characteristic, showing that it improves fertility, fecundity, and health, and abets other characteristics that were critical to reproductive success. We review research showing that positive mood offset is virtually universal in the nations of the world, even among people who live in extremely difficult circumstances. Positive moods increase the likelihood of the types of adaptive behaviors that likely characterized our Paleolithic ancestors, such as creativity, planning, mating, and sociality. Because of the ubiquity and apparent advantages of positive moods, it is a reasonable hypothesis that humans were selected for positivity offset in our evolutionary past. We outline additional evidence that is needed to help confirm that positive mood offset is an evolutionary adaptation in humans and we explore the research questions that the hypothesis generates.
This study investigates the influence of ultrasonic nanocrystal surface modification (UNSM) technique on the mechanical characteristics and fatigue life of two types of annealed and aged Inconel 718 ...alloys. The mechanical properties of both UNSM‐treated alloys were compared with the untreated specimens. The fatigue life of the untreated and UNSM‐treated Inconel 718 alloy specimens was investigated by ultrasonic fatigue and rotary‐bending fatigue tests. Results revealed that the UNSM‐treated specimens exhibited longer fatigue life than those of the untreated specimens. The improvement in fatigue life is mainly attributed to the induced compressive residual stress induced in the subsurface by UNSM technique.
Previous studies on self-enhancement bias used self-report measures to investigate individual and cultural differences in well-being. In the current research, we took a behavioral approach to analyze ...positive and negative perception tendencies between European Canadians, Asian Canadians and Koreans. In Study 1 and 2, participants were asked to bet on their expectation of success on a given task and then perform the task. The betting behaviors and actual performance were used to quantify positive and negative perception tendencies. In Study 1, we did not find cultural differences in positive and negative illusions. Positive self-perceptions were also not associated with higher self-reported well-being. In Study 2, we employed the same research design as Study 1, and we included a measure of perceived desirability to examine whether perceived desirability of the performance tasks are related to the two illusions indices. The results from Study 2 replicated the findings from Study 1, and perceived desirability did not influence the results. Our findings suggest that North Americans do not always exhibit more positive self-perceptions than Asians, suggesting that North Americans do not always view the self through rose-colored lenses.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Research has demonstrated that certain genotypes are expressed in different forms, depending on input from the social environment. To examine sensitivity to cultural norms regarding emotional support ...seeking as a type of social environment, we explored the behavioral expression of oxytocin receptor polymorphism (OXTR) rs53576, a gene previously related to socio-emotional sensitivity. Seeking emotional support in times of distress is normative in American culture but not in Korean culture. Consequently, we predicted a three-way interaction of culture, distress, and OXTR genotype on emotional support seeking. Korean and American participants (n = 274) completed assessments of psychological distress and emotional support seeking and were genotyped for OXTR. We found the predicted three-way interaction: among distressed American participants, those with the GG/AG genotypes reported seeking more emotional social support, compared with those with the AA genotype, whereas Korean participants did not differ significantly by genotype; under conditions of low distress, OXTR groups did not differ significantly in either cultural group. These findings suggest that OXTR rs53576 is sensitive to input from the social environment, specifically cultural norms regarding emotional social support seeking. These findings also indicate that psychological distress and culture are important moderators that shape behavioral outcomes associated with OXTR genotypes.
Cultural influences on personality TRIANDIS, Harry C; SUH, Eunkook M
Annual review of psychology,
01/2002, Letnik:
53, Številka:
1
Journal Article
Recenzirano
Ecologies shape cultures; cultures influence the development of personalities. There are both universal and culture-specific aspects of variation in personality. Some culture-specific aspects ...correspond to cultural syndromes such as complexity, tightness, individualism, and collectivism. A large body of literature suggests that the Big Five personality factors emerge in various cultures. However, caution is required in arguing for such universality, because most studies have not included emic (culture-specific) traits and have not studied samples that are extremely different in culture from Western samples.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, ODKLJ, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The present study examined cultural differences in the act of sharing positive events with others, called capitalization attempts. The first three studies tested whether capitalization attempts ...differ between two cultures using multiple methods: self-reports (Study 1), children’s storybooks (Study 2), and Facebook (Study 3). We found that Koreans are less likely to share their positive events with others than European Americans. Study 4 further examined the antecedents and consequences of capitalization attempts. We replicated the earlier findings that Koreans are hesitant to share their positive events and demonstrated that this is because Koreans are more concerned about the potential negative consequences for social relationships. Moreover, we found that the cultural differences in capitalization attempts partly account for mean-level differences in well-being between cultures. Implications for capitalization, culture, and well-being are discussed.
PDF
