| 1. |
- Lakhan, Abdullah, et al.
(författare)
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A Lightweight Secure Adaptive Approach for Internet-of-Medical-Things Healthcare Applications in Edge-Cloud-Based Networks
- 2022
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Ingår i: Sensors. - : MDPI Multidisciplinary Digital Publishing Institute. - 1424-8220. ; 22:6, s. 1-18
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Tidskriftsartikel (refereegranskat)abstract
- Mobile-cloud-based healthcare applications are increasingly growing in practice. For instance, healthcare, transport, and shopping applications are designed on the basis of the mobile cloud. For executing mobile-cloud applications, offloading and scheduling are fundamental mechanisms. However, mobile healthcare workflow applications with these methods are widely ignored, demanding applications in various aspects for healthcare monitoring, live healthcare service, and biomedical firms. However, these offloading and scheduling schemes do not consider the workflow applications’ execution in their models. This paper develops a lightweight secure efficient offloading scheduling (LSEOS) metaheuristic model. LSEOS consists of light weight, and secure offloading and scheduling methods whose execution offloading delay is less than that of existing methods. The objective of LSEOS is to run workflow applications on other nodes and minimize the delay and security risk in the system. The metaheuristic LSEOS consists of the following components: adaptive deadlines, sorting, and scheduling with neighborhood search schemes. Compared to current strategies for delay and security validation in a model, computational results revealed that the LSEOS outperformed all available offloading and scheduling methods for process applications by 10% security ratio and by 29% regarding delays.
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| 2. |
- Majumdar, Arnab, et al.
(författare)
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Pressure induced structural phase transition and piezochromism in photovoltaic sillen compounds PbBiO2X (X = Cl, Br & I)
- 2022
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Ingår i: APPLIED MATERIALS TODAY. - : Elsevier. - 2352-9407. ; 26
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Tidskriftsartikel (refereegranskat)abstract
- Hydrostatic pressure is an effective and clean method that can give rise to the emergence of novel crystal structures and physical properties. Thus, hydrostatic pressure can be used for designing new functional materials. Sillen materials or PbBiO2X (X = Cl, Br & I) are a class of materials which have gained considerable interest in the field of ferroelectrics, photocatalysis, etc . In this work, we have used first principles methods to predict the crystal structure and phase of sillen materials at different pressure points from 0 to 50 GPa. It was then followed by the study of their structural, electronic and optical properties upon compression. Upon compression, the band gaps decreased within a particular phase and showed kinks on phase transitions. In the compressed states, the band gaps are in the suitable range to be used in the visible range of the spectrum for photovoltaic properties. Piezochromism is also reported upon compression as can been seen from the changes in the optical absorption spectra. This work should remove any confusion with regards to the responsible phase at different pressures, and the possible existence of new phases with the respective band gaps should pave the way for future experimental works on photocatalysis and other energy applications. (c) 2022 The Author(s). Published by Elsevier Ltd.& nbsp;
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| 3. |
- Zidane, Mustapha, et al.
(författare)
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Determination and comparison of the electrical and thermal transport properties of BCC and FCC Fe-Ni based ternary alloys in the Earth's inner core
- 2022
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Ingår i: JOURNAL OF EARTH SYSTEM SCIENCE. - : Springer Nature. - 2347-4327 .- 0973-774X. ; 131:4
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Tidskriftsartikel (refereegranskat)abstract
- The Earth's core contains, in addition to iron, 5-10% nickel and many light elements such as C, O, Si and S, among others. For this work, we consider binary Fe-Ni alloys with 10% Ni as host material, doped with light elements as impurity atoms. The phases considered for the Fe-Ni host alloy are face-centered cubic (fcc) and body-centred cubic (bcc). At different concentrations of 2.5-50%, the impurity atoms C, O, Si and S were placed in the host Fe-Ni alloy to create ternary alloys. The resulting ternary systems are exposed to a pressure equivalent to that existing at the Earth's core. As shown by their formation energies, these alloys are stable and advantageous. The calculation of the resistivity of the impurities was performed with the help of the Kubo-Greenwood formula. Compared to fcc, in the case of bcc, electrical resistivities begin to saturate at about 30% of the atomic concentration of the impurities. Thermal conductivity was also determined from electrical resistivities calculated for varying concentrations and pressures according to Wiedemann-Franz law. In the case of compression, we observe a rise in thermal conductivity of about 1.5% of the core's internal pressure. The reported thermal conductivities support the notion of maintaining a convection-induced geodyanmo.
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| 4. |
- Zidane, Mustapha, et al.
(författare)
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Thermophysical properties of helium and hydrogen mixtures under high pressure predicted by ab-initio calculations : Implications for Saturn and Jupiter planets
- 2022
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Ingår i: Chemical Physics. - : Elsevier BV. - 0301-0104 .- 1873-4421. ; 555, s. 111430-
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Tidskriftsartikel (refereegranskat)abstract
- The thermodynamic and physical properties of Helium (He) and Hydrogen (H) mixtures are crucial form an astrophysical perspective. Nowadays, it is well known that these two elements constitute roughly 95% of the matter in the solar system. The high-pressure equation of He state doped with H is calculated in the framework of density functional theory (DFT) for three crystallographic structures. Namely, the Body Centered Cubic (BCC), Face Centered Cubic (FCC), and hexagonal close packed (HCP) structures have been studied. The equations of state (EOS) are provided for the He0.90H0.10 and He0.70H0.30 mixtures and the energy of the same mixtures are calculated with the earlier structures. The band structure for pressures of 0, 75 and 150 GPa were estimated by our calculations for the presumed crystal structures in the case of pure He and He0.70H0.30 mixture for comparison. The k(x) - k(y) cuts of the Bloch Spectral Functions (BSF) are presented for the pure He and He0.70H0.30 mixture for the three structures to explore the impact of doping on electronic properties. In addition, electrical resistivity calculations of the mentioned structures were carried out for mixtures with 10, 15, 20 and 30% of H. At final stage, the enthalpy (Delta H) of these latest mixtures have been deduced for the three crystal structures.
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