Accumulative roll‐Bonding (ARB) is a severe plastic deformation (SPD) process invented by the authors in order to fabricate ultrafine grained metallic materials. ARB is the only SPD process ...applicable to continuous production of bulky materials. In the process, 50 % rolled material is cut into two, stacked to be the initial dimension and then rolled again. In order to obtain one‐body solid material, the rolling in ARB is not only a deformation process but also a bonding process (roll‐bonding). By repeating this procedure, SPD of bulky materials can be realized. In this review paper, various kinds of new SPD mechanical properties of the ARB processed materials are indicated.
A comparison of accumulative roll bonding (ARB) and other severe plastic deformation processes for the formation of ultrafine‐grain (UFG) structures is the focus of this contribution; special stress is put on the role of shear deformation. The ARB process, the only SPD technology that uses rolling deformation itself, is suitable for producing the bulk UFG material continuously, and allows a closer insight into the formation mechanism and properties of such materials.
The present work was conducted to establish an initial understanding of the processing-microstructure-property relations for γ-TiAl manufactured by electron beam powder bed fusion. The investigation ...included microstructure characterization at different length scales of near-γ titanium aluminide Ti-48Al-2Cr-2Nb (in atom pct) in addition to evaluating the compressive strength, microstructures, fracture toughness, and fatigue crack growth behavior. Micro-CT revealed significant variations in the spatial distribution of internal defects along the build of the as-deposited sample, while HIP reduced these defects. However, inhomogeneous microstructures were exhibited in both the as-deposited and HIP materials while HIP processing reduced both the yield strength and amount of scatter in mechanical properties. Despite these observations, fracture toughness and fatigue crack growth results were in the range of those reported for conventionally cast material. The use of cloud computing provided an efficient means for data management, microstructure analytics, and collaboration among various contributors to the work.
•Bulk TiAl produced via EBM.•Microstructure evaluation using large area EBSD to characterize microstructure heterogeneity.•X-ray computerized tomography characterization of as deposited defects and effects of HIP.•Location specific fracture and fatigue behavior.•Effect of HIP treatments on microstructure, defects, and resulting fracture/fatigue behavior.
Abstract
The COSINE-100 experiment is designed to test the DAMA
experiment which claimed an observation of a dark matter signal from
an annual modulation in their residual event rate. To measure the
...1 %-level signal amplitude, it is crucial to control and monitor
nearly all environmental quantities that might systematically mimic
the signal. The environmental monitoring also helps ensure a stable
operation of the experiment. Here, we describe the design and
performance of the centralized environmental monitoring system for
the COSINE-100 experiment.
Modern electrochemical energy conversion devices require more advanced proton conductors for their broad applications. Phosphonated polymers have been proposed as anhydrous proton conductors for fuel ...cells. However, the anhydride formation of phosphonic acid functional groups lowers proton conductivity and this prevents the use of phosphonated polymers in fuel cell applications. Here, we report a poly(2,3,5,6-tetrafluorostyrene-4-phosphonic acid) that does not undergo anhydride formation and thus maintains protonic conductivity above 200 °C. We use the phosphonated polymer in fuel cell electrodes with an ion-pair coordinated membrane in a membrane electrode assembly. This synergistically integrated fuel cell reached peak power densities of 1,130 mW cm
at 160 °C and 1,740 mW cm
at 240 °C under H
/O
conditions, substantially outperforming polybenzimidazole- and metal phosphate-based fuel cells. Our result indicates a pathway towards using phosphonated polymers in high-performance fuel cells under hot and dry operating conditions.
At sixty-two meters the Leshan Buddha in southwest China is the
world's tallest premodern statue. Carved out of a riverside cliff
in the eighth century, it has evolved from a religious center to a
...UNESCO World Heritage Site and popular tourist destination. But
this Buddha does not stand alone: Sichuan is home to many cave
temples with such monumental sculptures, part of a centuries-long
tradition of art-making intricately tied to how local inhabitants
made use of their natural resources with purpose and creativity.
These examples of art embedded in nature have altered landscapes
and have influenced the behaviors, values, and worldviews of users
through multiple cycles of revival, restoration, and recreation. As
hybrid spaces that are at once natural and artificial, they embody
the interaction of art and the environment over a long period of
time.
This far-ranging study of cave temples in Sichuan shows that
they are part of the world's sustainable future, as their continued
presence is a reminder of the urgency to preserve culture as part
of today's response to climate change. Temples in the
Cliffside brings art history into close dialogue with current
discourse on environmental issues and contributes to a new
understanding of the ecological impact of artistic monuments.
Abstract Background There is a growing interest in the intersection of heart failure (HF) and frailty; however, estimates of the prevalence of frailty in HF vary widely. The purpose of this paper was ...to quantitatively synthesize published literature on the prevalence of frailty in HF and to examine the relationship between study characteristics (i.e. age and functional class) and the prevalence of frailty in HF. Methods The prevalence of frailty in HF, divided into Physical Frailty and Multidimensional Frailty measures, was synthesized across published studies using a random-effects meta-analysis of proportions approach. Meta-regression was performed to examine the influence of age and functional class (at the level of the study) on the prevalence of frailty. Results A total of 26 studies involving 6896 patients with HF were included in this meta-analysis. Despite considerable differences across studies, the overall estimated prevalence of frailty in HF was 44.5% (95% confidence interval, 36.2%–52.8%; z = 10.54; p < 0.001). The prevalence was slightly lower among studies using Physical Frailty measures (42.9%, z = 9.05; p < 0.001) and slightly higher among studies using Multidimensional Frailty measures (47.4%, z = 5.66; p < 0.001). There were no significant relationships between study age or functional class and prevalence of frailty. Conclusions Frailty affects almost half of patients with HF and is not necessarily a function of age or functional classification. Future work should focus on standardizing the measurement of frailty and on broadening the view of frailty beyond a strictly geriatric syndrome in HF.
We report on magnetization M (H), dc and ac magnetic susceptibility χ(T) , specific heat C m (T) and muon spin relaxation (μSR) measurements of the Kitaev honeycomb iridate Cu2IrO3 with quenched ...disorder. In spite of the chemical disorders, we find no indication of spin glass down to 260 mK from the Cm(T) and μ SR data. Furthermore, a persistent spin dynamics observed by the zero-field muon spin relaxation evidences an absence of static magnetism. The remarkable observation is a scaling relation of χH,T and MH, T in H/T with the scaling exponent α = 0.26–0.28 , expected from bond randomness. However, Cm H, T/T disobeys the predicted universal scaling law, pointing towards the presence of additional low-lying excitations on the background of bond-disordered spin liquid. Our results signify a many-faceted impact of quenched disorder in a Kitaev spin system due to its peculiar bond character.
A low level of CD4+ lymphocyte cells makes end-stage HIV/AIDS patients highly susceptible to microbial infections. We have adopted the next generation sequencing method to identify the spectrum of ...bacterial plasma and viral elements that might be present in these patients. The HIV/AIDS plasma microbiome was dominated by bacterial elements in the taxonomical order Pseudomonadales, while healthy people carried fewer bacterial DNA in the plasma. We have found that many of the bacterial elements in HIV/AIDS plasma are similar to those of the microbes found in the human gut, suggesting potential acquisition of microbial elements from the gut. The HIV/AIDS and normal plasma DNA virome shared some similarities in the presence of common ubiquitous eukaryotic viruses. The normal DNA virome was mainly composed of viruses from Anelloviridae. In contrast, the HIV/AIDS DNA virome contained a large proportion of bacteriophages, endogenous retroviruses and a non-human virus. In addition, several sequences, which might belong to novel bacteria or endogenous retroviruses, were identified. Taken together, the use of high-throughput sequencing technology in unveiling microbial metagenomics may facilitate future research in combating HIV/AIDS and its associated microbial complications.
ABSTRACT In the current paradigm, it is believed that the compact VLBI radio core of radio-loud active galactic nuclei (AGNs) represents the innermost upstream regions of relativistic outflows. These ...regions of AGN jets have generally been modeled by a conical outflow with a roughly constant opening angle and flow speed. Nonetheless, some works suggest that a parabolic geometry would be more appropriate to fit the high energy spectral distribution properties and it has been recently found that, at least in some nearby radio galaxies, the geometry of the innermost regions of the jet is parabolic. We compile here multi-frequency core sizes of archival data to investigate the typically unresolved upstream regions of the jet geometry of a sample of 56 radio-loud AGNs. Data combined from the sources considered here are not consistent with the classic picture of a conical jet starting in the vicinity of the super-massive black hole (SMBH), and may exclude a pure parabolic outflow solution, but rather suggest an intermediate solution with quasi-parabolic streams, which are frequently seen in numerical simulations. Inspection of the large opening angles near the SMBH and the range of the Lorentz factors derived from our results support our analyses. Our result suggests that the conical jet paradigm in AGNs needs to be re-examined by millimeter/sub-millimeter VLBI observations.
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