219 research outputs found

    The equations of some dispersionless limit

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    This short article presents a table of new equations which can be regarded as the generalized equations of the dispersionless limit of several nonlinear equations. From the definition expressed in an algebraic formula, one can get an equation for any positive numbers p and q. The equations were calculated by using the computers and were examined by hand-calculation up to p=10. Relations with some dispersionless hierarchies are mentioned.Comment: AmSTeX, 6 pages, amsppt.st

    Effectiveness of vaccination and quarantine policies to curb the spread of COVID-19

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    A pandemic, the worldwide spread of a disease, can threaten human beings from the social as well as biological perspectives and paralyze existing living habits. To stave off the more devastating disaster and return to a normal life, people make tremendous efforts at multiscale levels from individual to worldwide: paying attention to hand hygiene, developing social policies such as wearing masks, social distancing, quarantine, and inventing vaccines and remedy. Regarding the current severe pandemic, namely the coronavirus disease 2019, we explore the spreading-suppression effect when adopting the aforementioned efforts. Especially the quarantine and vaccination are considered since they are representative primary treatments for block spreading and prevention at the government level. We establish a compartment model consisting of susceptible (S), vaccination (V), exposed (E), infected (I), quarantined (Q), and recovered (R) compartments, called SVEIQR model. We look into the infected cases in Seoul and consider three kinds of vaccines, Pfizer, Moderna, and AstraZeneca. The values of the relevant parameters are obtained from empirical data from Seoul and clinical data for vaccines and estimated by Bayesian inference. After confirming that our SVEIQR model is plausible, we test the various scenarios by adjusting the associated parameters with the quarantine and vaccination policies around the current values. The quantitative result obtained from our model could suggest a guideline for policy making on effective vaccination and social policies.Comment: 8 pages, 5 figure

    Orthogonal Stability of an Additive-quartic Functional Equation in Non-Archimedean Spaces

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    Using fixed point method, we prove the Hyers-Ulam stability of the orthogonally additive-quartic functional equation f(2x+y)+ f(2x-y)=4 f(x+y)+ 4 f(x-y) + 10 f(x) + 14f(-x) - 3 f(y)-3f(-y) for all x,yx, y with xperpyxperp y, in non-Archimedean Banach spaces. Here perpperp is the orthogonality in the sense of Rätz

    Out-of-Plane Strengthening of Unreinforced Masonry Walls by Glass Fiber-Reinforced Polyurea

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    Fiber-reinforced polymer reinforcement or polyurea reinforcement techniques are applied to strengthen unreinforced masonry walls (UMWs). The purpose of this experimental study is to verify the out-of-plane reinforcing effect of sprayed glass fiber-reinforced polyurea (GFRPU), which is a composite elastomer made of polyurea and milled glass fibers on UMW. The out-of-plane strengths and ductile behaviors based on various coating shapes are compared in this study. An empirical formula to describe the degree of reinforcement on the out-of-plane strength of the UMW is derived based on the experimental results. It is observed that the peak load-carrying capacity, ductility, and energy absorption capacity gradually improve with an increase in the strengthening degree or area. Compared with the existing masonry wall reinforcement method, the GFRPU technique is a construction method that can help improve the safety performance along with ease of construction and economic efficiency. Doi: 10.28991/CEJ-2022-08-01-011 Full Text: PD

    In-Plane Strengthening of Unreinforced Masonry Walls by Glass Fiber-Reinforced Polyurea

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    Strengthening techniques have been employed in Korea to unreinforced masonry walls (UMWs) for several years to protect them from damage caused by the intermittent occurrence of earthquakes. Polyurea, which has a high tensile strength and elongation rate, can be utilized as a strengthening material to enhance the in-plane strength and ductility of UMWs. Glass fiber-reinforced polyurea (GFRPU) is a composite elastomer manufactured by progressively adding milled glass fiber to polyurea. The purpose of this study is to investigate the enhancement of the in-plane strength and ductility of UMWs using GFRPU, depending on the shape of the GFRPU coating on the wall. Four masonry wall specimens are tested with test variables of the number of strengthening sides and coating shapes. It is illustrated that the GFRPU reinforcement of masonry wall leads to enhanced load-carrying capacity, ductility, and energy absorption. An empirical formula to represent the degree of strengthening effected by GFRPU is proposed in this study. Doi: 10.28991/cej-2021-03091782 Full Text: PD

    New Heteroleptic Cobalt Precursors for Deposition of Cobalt-Based Thin Films

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    A new series of heteroleptic complexes of cobalt were synthesized using aminoalkoxide and ??-diketonate ligands. The complexes, [Co(dmamp)(acac)]2 (3), [Co(dmamp)(tfac)]2 (4), [Co(dmamp)(hfac)]2 (5), [Co(dmamp)(tmhd)]2 (6), and [Co(dmamb)(tmhd)]2 (7), were prepared by two-step substitution reactions and studied using Fourier transform infrared spectroscopy, mass spectrometry, elemental analysis, and thermogravimetric analysis (TGA). Complexes 3-7 displayed dimeric molecular structures for all of the complexes with cobalt metal centers interconnected by ??2-O bonding by the alkoxy oxygen atom. TGA and a thermal study of the complexes displayed high volatilities and stabilities for complexes 6 and 7, with sublimation temperatures of 120 ??C/0.5 Torr and 130 ??C/0.5 Torr, respectively

    Mechanisms of an extraordinary East Asian summer monsoon event in July 2011

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    Previous studies have demonstrated that the strong East Asian summer monsoon results mainly from the westward intensification of the North Pacific subtropical high (NPSH), or equivalently, the enhancement of the western North Pacific subtropical high. However, during early July in 2011 a strong southerly or southeasterly moist flow gave rise to a large amount of precipitation over southwestern Japan and Korea and anomalous dry conditions over central China because of the extraordinary intensification of the NPSH to the north. The formation of the anomalous high that occurred to the east of central Japan during early July is very rare, and its physical mechanisms are investigated in this study. The regressed circulation anomalies and wave-activity flux vectors for July 2011 and data from the previous 32 years show that two teleconnection patterns due to Rossby wave trains are the most important mechanisms: Rossby wave propagation from the eastern North Atlantic and western Europe to East Asia following the North Eurasian jet and East Asian jet in the upper level, and northward propagation of Rossby waves forced by diabatic heating over the western North Pacific (WNP) region in the lower level. This simultaneous forcing of a significant negative phase of the summertime North Atlantic Oscillation in the higher latitudes and enhanced diabatic heating over the subtropical WNP is found to be the cause of the abnormal development of the anomalous high to the east of central Japan, resulting in extremely wet conditions in Korea and southern Japan and dry conditions in southern China

    Transient receptor potential channel TRPV4 mediates TGF-β1-induced differentiation of human ventricular fibroblasts

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    Background: Cardiac fibroblasts (CFs) are principal extracellular matrix-producing cells. In response to injury, CFs transdifferentiate into myofibroblasts. Intracellular calcium (Ca2+) signaling, involved in fibroblast proliferation and differentiation, is activated in fibroblasts through transient receptor potential (TRP) channels, but the function of these channels has not been investigated in human ventricular CFs. Under evaluation in this study, was the role of TRP channels in the differentiation of human ventricular CFs induced by transforming the growth factor beta (TGF-β), a pro-fibrotic cytokine. Methods: Human ventricular CFs were used in this study. The differentiation of CFs into myofibroblast was induced with TGF-β and was identified by the expression of smooth muscle actin. Results: Results indicate that Ca2+ signaling was an essential component of ventricular CF dif­ferentiation. CFs treated with TGF-β demonstrated increased expression of a TRP channel, TRPV4, both at the mRNA and protein levels, which corresponded with CF-myofibroblast trans-differentiation, as evidenced by the upregulation of α-smooth muscle actin, a myofibroblast marker, and plasminogen activator inhibitor-1, which are fibrogenesis markers. An agonist of TRPV4 induced the conversion of CFs into myofibroblasts, whereas it’s antagonist as well a Ca2+ chelating agent reduced it, indicating that the Ca2+ influx throughTRPV4 is required for CF trans-differentiation. Overall, these results dem­onstrate that TRPV4-mediated Ca2+ influx participates in regulating the differentiation of human ventricular CFs into myofibroblasts through the MAPK/ERK pathway. Conclusions: Overall, these results demonstrate that TRPV4-mediated Ca2+ influx participates in regulating the differentiation of human ventricular CFs into myofibroblasts through the MAPK/ERK pathway
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