An efficient and provably secure authenticated key agreement scheme for mobile edge computing

Wireless Networks - Though Mobile Cloud Computing (MCC) and Mobile Edge Computing (MEC) technologies have brought more convenience to mobile services over past few years, but security concerns like...     

Sixty-four years of informetrics research: productivity,impact and collaboration

This paper analyses the information science research field of informetrics to identify publication strategies that have been important for its successful researchers. The study uses a micro-analysis of informetrics researchers from 5,417 informetrics papers published in 7 core informetrics journals during 1948–2012. The most productive informetrics researchers were analysed in terms of productivity, citation impact, and co-authorship. The 30 most productive informetrics researchers of all time span several generations and seem to be usually the primary authors of their research, highly collaborative, affiliated with one institution at a time, and often affiliated with a few core European centres. Their research usually has a high total citation impact but not the highest citation impact per paper. Perhaps surprisingly, the US does not seem to be good at producing highly productive researchers but is successful at producing high impact researchers. Although there are exceptions to all of the patterns found, researchers wishing to have the best chance of being part of the next generation of highly productive informetricians may wish to emulate some of these characteristics.     

What can Bookmetrix tell us about the impact of Springer Nature’s books

Scientometrics - This paper reports on book impact assessment using bibliometrics, usage metrics and altmetrics. The objective of the study is to investigate the citation, usage, reach and...     

Preparation,characterization and in vitro biological response of simultaneous co-substitution of Zr+4/Sr+2 58S bioactive glass powder

In the present study, structure of zirconium-containing bioactive glass (58S-BG (Zr-BG)) with optimal fixed Zr content (5 mol.%) was modified by incorporation of strontium (Sr). These Zr and Sr-containing BGs (ZS-BGs) were synthesized by sol-gel method and substitution of Ca with modifier ions (Sr content = 0, 3, 6, 9, and 12 mol.%). The results obtained from characterization by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared (FTIR), and energy-dispersive X-ray spectroscopy (EDS) techniques from surface of all the ZS-BGs revealed formation of hydroxyapatite (HA) after 7 days of immersion in the simulated body fluid (SBF) solution. Evaluation of changes in the SBF solution, by monitoring pH variations and ions? concentration, was in agreement with the results of morphological and structural investigations. The in-vitro biological function of synthesized BGs was studied through (MTT) assay and alkaline phosphatase (ALP) activity analysis. The results showed that all the specimens significantly stimulated proliferation and viability of MC3T3 osteoblast-like cells. Furthermore, antibacterial studies confirmed less resistance of methicillin-resistant Staphylococcus aureus (MRSA) bacteria against ZS-BGs. Eventually, the results of in-vitro bio-analysis were clarified and confirmed by two cell staining techniques of Live/Dead and Dapi/Actin. This confirmation was achieved by observing the increased quantity of live cells and their nuclei as well as the decreased number of dead cells after co-culturing with all ZS-BGs.     

Cyclic Behaviour of Fully-Rigid and Semi-Rigid Steel Beam-to-Column Connections

A test program was considered to clarify the cyclic characteristics of eight full-scale unstiffened extended end-plates with variable parameters and one SidePlate moment connection. All specimens were subjected to 2010 AISC seismic provision loading protocol where flexural strengths were identified at each interstorey drift angle. The results showed that all unstiffened extended end-plate failed to develop full inelastic capacity of connected beams and plastic hinges mainly appeared in the connection’s components. On the other hand, the SidePlate moment connection had the capacity to develop adequate interstorey drift angles up to 0.06 rad, indicating that this type of connection possesses sufficient stiffness and strength to be classified as a rigid and full-strength connection. The results also showed that SidePlate possesses considerably more energy dissipation capacity and an equivalent hysteretic damping ratio compared to unstiffened extended end-plate specimens, especially at higher interstorey drift angles.     

Shear stress distribution prediction in symmetric compound channels using data mining and machine learning models

Shear stress distribution prediction in open channels is of utmost importance in hydraulic structural engineering as it directly affects the design of stable channels. In this study, at first, a series of experimental tests were conducted to assess the shear stress distribution in prismatic compound channels. The shear stress values around the whole wetted perimeter were measured in the compound channel with different floodplain widths also in different flow depths in subcritical and supercritical conditions. A set of, data mining and machine learning algorithms including Random Forest (RF), M5P, Random Committee, KStar and Additive Regression implemented on attained data to predict the shear stress distribution in the compound channel. Results indicated among these five models; RF method indicated the most precise results with the highest R² value of 0.9. Finally, the most powerful data mining method which studied in this research compared with two well-known analytical models of Shiono and Knight method (SKM) and Shannon method to acquire the proposed model functioning in predicting the shear stress distribution. The results showed that the RF model has the best prediction performance compared to SKM and Shannon models.     

EFFECT OF SURFACTANTS ON KINETICS OF β-CAROTENE PHOTODEGRADATION IN EMULSIONS

The effect of surfactant type on photodegradation kinetics of β-carotene in oil-in-water emulsions has been investigated. The stabilized emulsions of lecithin, sodium stearoyl 2-lactylate (SSL), and polyoxyethylene sorbitan monolaurate (Tween-20) together with a β-carotene solution in corn oil were exposed to illumination. The rate of photochemical degradation was mathematically modeled by regression fitting. The lecithin-stabilized emulsion showed higher light fastness than the other samples. β-carotene photodegradation reaction followed a zero-order kinetic model for oil-based systems and lecithin emulsions, while β-carotene degraded by a first-order reaction in SSL and Tween-20 emulsions. Thermodynamic parameters revealed that water-based samples are more heat sensitive than oil-based samples. An isokinetic relationship was observed between the samples. Moreover, results indicated mixing of SSL and Tween-20 with lecithin leads to better protection of β-carotene than emulsions stabilized with SSL or Tween-20, separately.     

Microstructure evolution in cast and equilibrium heat-treated CuZn30-(Si) alloys

Abstract

The main object of this work was to investigate the effect of Si addition and heat treatment on the microstructure of CuZn30 alloy. The alloys were prepared by casting and then the chemical composition, microstructure and phases were determined by optical and scanning electron microscope and XRD analysis. The resulting microstructures contained two phases, α and β′, with volume fraction depending on silicon content. Increments of Si content led to the formation of a Widmanst?tten structure. It was also found that the silicon dissolved completely in α + β phases and the lattice parameters of both α- and β′-phases increased as the Si content increased. Hardness tests showed that hardness of both the as-cast and heat-treated samples increased as the Si content increased, and a significant increment of hardness in heat-treated alloy was due to the formation of a martensite phase.     

Trans Z-source-based half-bridge inverter: A method for achieving high voltage gain

This article offers a modified trans Z-source-based half-bridge inverter topology. A suitable pulse width modulation (PWM)-based control method is applied on the proposed inverter. Regarding this control technique, the state of switches in each of the operational states is obtained, and their equivalent control circuits are demonstrated and examined in depth. With the help of the results of these analyses, the boost factor for the proposed structure can be calculated. Additionally, the necessary equations for designing the passive components, as well as the power ratings of the active components, are found. Then, in order to evaluate the advantages and disadvantages of the proposed topology, a comparative study is conducted in several aspects, including the boost factor, the voltage stresses on capacitors, and the voltage stresses on passive devices. This comparison demonstrates that the proposed topology provides a high boost factor while minimizing voltage stresses on the devices, resulting in a smaller volume and size and a lower cost. Once the proposed topology has been thoroughly analyzed, the total power losses and the percentages of power losses consumed by each component device are calculated to obtain efficiency. Finally, an experimental prototype based on the equations for passive and active components is developed. Experiments are used to verify the validity of the proposed topology and the accuracy of the equations.     

Post-buckling optimization of two-dimensional functionally graded porous beams

International Journal of Mechanics and Materials in Design - In the present study, an attempt is made to present the governing equations on the post-buckling of two-dimensional (2D) FGP beams and...