Dzyaloshinskii-Moriya interaction in Nd2_{2}Fe14_{14}B as the origin of spin reorientation and rotating magnetocaloric effect

The mechanism of spin reorientation in Nd$_{2}$Fe$_{14}$B, which is a host crystal of a well-known neodymium permanent magnet, is studied by combining first-principles calculations and Monte Carlo simulations. The spin reorientation is thought to be derived from crystal field effects and gets less attention because of the undesirable property for hard magnet application. Dzyaloshinskii-Moriya interactions are usually less attractive or often ignored in rare-earth bulk systems, including permanent magnets such as Nd$_{2}$Fe$_{14}$B since people believe that the magnetic anisotropy is more dominant than the Dzyaloshinskii-Moriya interactions. However, in this study, we have found, for the first time, that the spin reorientation in Nd$_{2}$Fe$_{14}$B is attributed to Dzyaloshinskii-Moriya interactions. We have found, furthermore, the spin reorientation in Nd$_{2}$Fe$_{14}$B yields a great stage of rotating magnetocaloric effect at practical application level. We have found that the Dzyaloshinskii-Moriya interactions definitely contributes to the physical properties as a non-negligible effect in magnetic materials

Anisotropic magnetocaloric effect of CrI3_{3}: A theoretical study

CrI$_{3}$ is considered to be a promising candidate for spintronic devices and data storage. We derived the Heisenberg Hamiltonian for CrI$_{3}$ from density functional calculations using the Liechtenstein formula. Moreover, the Monte--Carlo simulations with the Sucksmith--Thompson method were performed to analyze the effect of magnetic anisotropy energy on the thermodynamic properties. Our method successfully reproduced the negative sign of isothermal magnetic entropy changes when a magnetic field was applied along the hard plane. We found that the temperature dependence of the magnetocrystalline anisotropy energy is not negligible at temperatures slightly above the Curie temperature. We clarified that the origin of this phenomenon is attributed to anisotropic magnetic susceptibility and magnetization anisotropy. The difference between the entropy change of the easy axis and the hard plane is proportional to the temperature dependence of the magnetic anisotropy energy, implying that the anisotropic entropy term is the main source of the temperature dependence of the free energy difference when magnetizing in a specific direction other than the easy axis. We also investigated the magnetic susceptibility that can be used for the characterization of the negative sign of the entropy change in the case of a hard plane. The competition of magnetocrystalline anisotropy energy and external magnetic field at low temperature and low magnetic field region causes a high magnetic susceptibility as the fluctuation of magnetization. Meanwhile, the anisotropy energy is suppressed at a sufficient magnetic field applied along the hard axis, the magnetization is fully rotated to the direction of the external magnetic field

Effect of magnetocrystalline anisotropy on magnetocaloric properties of AlFe2_{2}B2_{2} compound

It is well known that the temperature dependence of the effective magnetocrystalline anisotropy energy obeys the $l(l+1)/2$ power law of magnetization in the Callen-Callen theory. Therefore, according to the Callen-Callen theory, the magnetocrystalline anisotropy energy is assumed to be zero at the critical temperature where the magnetization is approximately zero. This study estimates the temperature dependence of the magnetocrystalline anisotropy energy by integrating the magnetization versus magnetic field ($M$--$H$) curves, and found that the magnetocrystalline anisotropy is still finite even above the Curie temperature in the uniaxial anisotropy, whereas this does not appear in the cubic anisotropy case. The origin is the fast reduction of the anisotropy field, which is the magnetic field required to saturate the magnetization along the hard axis, in the case of cubic anisotropy. Therefore, the magnetization anisotropy and anisotropic magnetic susceptibility, those are the key factors of magnetic anisotropy, could not be established in the case of cubic anisotropy. In addition, the effect of magnetocrystalline anisotropy on magnetocaloric properties, as the difference between the entropy change curves of AlFe$_{2}$B$_{2}$ appears above the Curie temperature, which is in good agreement with a previous experimental study. This is proof of magnetic anisotropy at slightly above Curie temperature

INVESTIGATION ON HYDROLOGIC PERFORMANCE OF PERVIOUS CONCRETE PAVEMENT BY FINITE ELEMENT ANALYSIS

Pervious concrete pavement has been used widely as an effective practice for water management in low-impact development techniques. The hydrologic performance of pervious concrete pavement depends significantly on the rainfall intensity and the designed slope. This study assessed the hydrologic performance of pervious concrete pavement by evaluating the time for surface ponding via finite element analysis. A series of simulations were carried out to explore the relationship between hydrologic performance and pervious concrete pavement by the Hydrus 2D program. The research’s results showed that as the slope increased, the time of surface ponding also increased. The data indicated that the slope variable had a low impact on the water level in pervious concrete pavement under a constant rainfall intensity. Observation of the effect of rainfall intensity showed that when the rainfall intensity increased twofold, the time for surface ponding dropped about two times. Furthermore, when surface ponding appeared, pervious concrete pavement at higher rainfall intensity had lower water content. The rainfall intensity also significantly affects the hydrologic performance of the pervious concrete pavement. This study only assessed the hydrologic performance by using the time for surface ponding via finite element analysis. Further experimental studies should be conducted to examine the relationship of other factors to the hydrologic performance of pervious concrete pavement

THE IMPACT OF NATIONAL CULTURE ON BILATERAL TRADE IN VIETNAM

The purpose of this paper is to examine whether or to what extent national culture influences bilateral trade flows between Vietnam and its trading partners. Using a panel dataset of 52 countries from 2001 till 2011 and six cultural dimensions of Hofstede, the regression analysis performed by gravity model shows that national culture and bilateral trade flows between Vietnam and trading partners are significantly correlated. This study's implications may help macro-policy makers devise better export promotion policies and boost the volume of bilateral trade between Vietnam and other countries around the world

Climate-induced storminess forces major increases in future storm surge hazard in the South China Sea region

Coastal floods, driven by extreme sea levels, are one of the most dangerous natural hazards. The people at highest risk are those living in low-lying coastal areas exposed to tropical-cyclone-forced storm surges. Here we apply a novel modelling framework to estimate past and/or present and future storm-surge-level and extreme-sea-level probabilities along the coastlines of southern China, Vietnam, Cambodia, Thailand, and Malaysia. A regional hydrodynamic model is configured to simulate 10 000 years of synthetic tropical cyclone activity, representative of a past/present (1980–2017) and high-emission-scenario future (2015–2050) period. Results show that extreme storm surges, and therefore total water levels, will increase substantially in the coming decades, driven by an increase in the frequency of intense tropical cyclones. Storm surges along the southern Chinese and northern and southern Vietnamese coastlines increase by up to 1 m, significantly larger than expected changes in mean sea-level rise over the same period. The length of coastline that is presently exposed to storm surge levels of 2.5 m or greater will more than double by 2050. Sections of Cambodian, Thai, and Malaysian coastlines are projected to experience storm surges (at higher return periods) in the future, not previously seen, due to a southward shift in tropical cyclone tracks. Given these findings, coastal flood management and adaptation in these areas should be reviewed for their resilience against future extreme sea levels

A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

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A Deep Neural Network for Simultaneous Estimation of b Jet Energy and Resolution

We describe a method to obtain point and dispersion estimates for the energies of jets arising from b quarks produced in proton-proton collisions at an energy of s = 13 TeV at the CERN LHC. The algorithm is trained on a large sample of simulated b jets and validated on data recorded by the CMS detector in 2017 corresponding to an integrated luminosity of 41 fb - 1 . A multivariate regression algorithm based on a deep feed-forward neural network employs jet composition and shape information, and the properties of reconstructed secondary vertices associated with the jet. The results of the algorithm are used to improve the sensitivity of analyses that make use of b jets in the final state, such as the observation of Higgs boson decay to b b ¯

Дослідження ерозії вапняку на островах кат ба на Північному Сході В'єтнаму з використанням вимiрювача поперечної мікро-ерозії

Erosion rate at the Cat Ba island stations ranged from 0.196 to 0.282 mm/year shows that the average value in comparison with previous study results ranges from ±0.2 to ±0.5 mm with strong eroded level. Relative erosion rate value is the lowest at measuring stations X2 on April 8th, 2015 and the highest is at measuring stations Z7 on November 9th 2015, the average value in comparison with previous study results, ranges from ±0.05 to ±0.2 mm with average eroded level and from ±0.2 to ±0.5 mm with strong eroded level.The results of relative erosion rate on April 8th, 2015 are lower than on November 9th, 2015. Total rainfall values counted from the beginning of the study to the first measuring date (April 8th, 2015) and the second measuring date (November 9th, 2015) are 980.2 mm and 2280 mm, respectively. Therefore, the erosion rate of limestone is strongly affected by changes of total rainfall on the Cat Ba Island.Average relative erosion rates in this study are quite high at some submerged zone stations (about over 0.2 mm/year, on average) and quite low with some stations on land in comparison with some previous studies all over the world. Therefore, it needs more assessment in longer period to study more accurately some other impacts on weathering and erosion processes.В последние годы карстовые ландшафты острова Кат Ба подверглись значительному воздействию вследствие интрузии и глобальных изменений климата. Естественное разрушение карстовых ландшафтов в результате эрозии известняка становится все более распространенной проблемой. Поэтому необходимо углубить исследования методов защиты для эффективного сохранения ландшафтов.В останні роки карстові ландшафти острова Кат Ба зазнали значного впливу внаслiдок iнтрузiї та глобальних змін клімату. Природне руйнування карстових ландшафтів в результатi ерозії вапняку стає все більш росповсюдженою проблемою. Тому необхідно поглибити дослідження методів захисту для ефективного збереження ландшафтів

Caractérisation des propriétés mécaniques de la peau humaine in vivo via l'IRM

La peau est un matériau complexe, constituée de trois couches (épiderme, derme et hypoderme) et posée sur les muscles. La combinaison d'une technique d'indentation et d'IRM a été développée. Des tests d'indentation ont été effectués sur l'avant-bras gauche de 9 sujets (de 26 à 40 ans). Les images issues de l'IRM ont été traitées via un logiciel de traitement d'images développé en interne. La modélisation par EF à partir des images IRM a été réalisée grâce à un pré-post processeur MSC.Patran et un solveur MSC.Marc. La loi de comportement (LDC) hyperélastique incompressible de type de Néo-Hooke (C1O) a été utilisée. L'identification des paramètres de la LDC a été réalisée grâce à un algorithme de minimisation de Levenberg-Marquardt. La validation numérique a montré que le minimum est unique lorsque l'épiderme et le derme se comportent comme une couche. Les résultats d'identification pour une population de 9 sujets sont: ClO,E+D=[60-370] kPa ; ClO,Hyp.=[0,04-4] kPa ; C1O,Mus.=[0,7-1,7] kPa.The skin is a complex material, consists of three layers (epidermis, dermis and hypodermis) and lies on muscle. The combination of an indentation and MRI techniques has been developed. Indentation tests were performed on the left forearm of 9 subjects (from 26 to 40 years-olds). The images from MRI were processed via images processing software developed in house. FE Modeling trom the MRI images was conducted through MSC.Patran pre-processor and MSC.Marc solver. The NeoHooke hyperelastic incompressible constitutive law (ClO) has been used. The parameters identification of constitutive law was performed through Levenberg-Marquardt minimization algorithm. The numerical validation showed that the minimum is unique when the epidermis and dermis behave as one layer. The results of identification for a population of 9 subjects are: ClO,E+D=[60-370] kPa; CIO,Hyp.=[0.04-4] kPa; ClO,Mus.=[0.7-1.7] kPa.COMPIEGNE-BU (601592101) / SudocSudocFranceF