Investigation of Sm2O3 additive on mechanical and electrical properties of Li2O‐ stabilized β″‐alumina electrolyte

Li₂O‐ stabilized β″‐alumina was synthesized by the double zeta process. The effect of Sm₂O₃ additive as the sintering aid, on microstructure, mechanical and electrical properties of Li₂O‐ stabilized β″‐alumina ceramics was studied by means of X‐ray diffraction, field emission scanning electron microscope, biaxial flexure test and ionic conductivity measurement. The results indicated that both the fracture strength and the ionic conductivity of the sample containing 0.2 wt% Sm₂O₃ improved approximately 52% and 54%, respectively, that can be attributed to its higher density, higher amount of β″‐Al₂O₃ phase and more uniform microstructure.     

Flocking Algorithms in Networks with Directed Switching Velocity Interaction Topologies

This paper studies flocking algorithms for multi‐agent systems with directed switching velocity interaction topologies. It is assumed that the position information of each agent is available for agents within its neighborhood region of radius r, however, they communicate the velocity information between each other through unidirectional links modeled by a particular class of directed topologies. A new energy function is defined to analyze the global stability and a sufficient condition is derived for asymptotic flocking in the face of switching topologies. The proposed control strategy guarantees the achievement of desired formations, while avoiding collisions among agents. It also ensures velocity agreement under suitable conditions in a variety of real networks with greatly reduced velocity data exchange. Moreover, a leader‐follower framework is formulated for the described class of interaction topologies and it is shown that a more relaxed condition is required to achieve the desired performance. Finally, several simulations are performed to illustrate and confirm the theoretical results obtained.     

Properties of Poly(vinyl chloride)/poly(ethylene oxide)/polyaniline Conductive Films: The Effect of Poly(ethylene glycol) Diglycidyl Ether

The effect of polyaniline and poly(ethylene glycol) diglycidyl ether on tensile properties, morphology, thermal degradation, and electrical conductivity of poly(vinyl chloride)/poly(ethylene oxide)/polyaniline conductive films was studied. The poly(vinyl chloride)/poly(ethylene oxide)/polyaniline conductive films were prepared using a solution casting technique at room temperature until a homogeneous solution was produced. Poly(vinyl chloride)/poly(ethylene oxide)/polyaniline/poly(ethylene glycol) diglycidyl ether conductive films exhibit higher electrical properties, tensile strength, modulus of elasticity but lower final decomposition temperature than poly(vinyl chloride)/poly(ethylene oxide)/polyaniline conductive films. Scanning electron microscopy morphology showed that the polyaniline more widely dispersed in the poly(vinyl chloride)/poly(ethylene oxide) blends with the addition of poly(ethylene glycol) diglycidyl ether as surface modifier.     

A robust hybrid fuzzy–simulated annealing–intelligent water drops approach for tuning a distribution static compensator nonlinear controller in a distribution system

This article presents a novel hybrid optimization approach for a nonlinear controller of a distribution static compensator (DSTATCOM). The DSTATCOM is connected to a distribution system with the distributed generation units. The nonlinear control is based on partial feedback linearization. Two proportional-integral-derivative (PID) controllers regulate the voltage and track the output in this control system. In the conventional scheme, the trial-and-error method is used to determine the PID controller coefficients. This article uses a combination of a fuzzy system, simulated annealing (SA) and intelligent water drops (IWD) algorithms to optimize the parameters of the controllers. The obtained results reveal that the response of the optimized controlled system is effectively improved by finding a high-quality solution. The results confirm that using the tuning method based on the fuzzy-SA-IWD can significantly decrease the settling and rising times, the maximum overshoot and the steady-state error of the voltage step response of the DSTATCOM. The proposed hybrid tuning method for the partial feedback linearizing (PFL) controller achieved better regulation of the direct current voltage for the capacitor within the DSTATCOM. Furthermore, in the event of a fault the proposed controller tuned by the fuzzy-SA-IWD method showed better performance than the conventional controller or the PFL controller without optimization by the fuzzy-SA-IWD method with regard to both fault duration and clearing times.     

Biosynthesis of bimetallic and core–shell nanoparticles: their biomedical applications – a review

Recently, researchers succeeded in designing and manufacturing a new class of nanoparticles (NPs) called hybrid NPs. Among hybrid NPs, bimetallic and core–shell NPs were a revolutionary step in NPs science. A large number of green physiochemical and methods for nanostructures synthesis have been published. Eventually, physiochemical methods are either expensive or require the use of chemical compounds for the synthesis of bimetallic and core–shell nanostructures. The main challenges that scientists are facing are making the process cheaper, facile and eco‐friendly efficient synthesis process. Green synthesis (biosynthesis) refers to the use of bio‐resources (such as bacteria, fungi, plants or their derivatives) for the synthesis of nanostructures. The popularity of the green synthesis of nanostructures is due to their environmental friendliness and no usage of toxic materials, environmental friendliness for the synthesis or stability of nanostructure. Bimetallic and core–shell NPs have many biomedical applications such as removing heavy metals, parasitology, molecular and microbial sensor, gene carrier, single bacterial detection, oligonucleotide detection and so on. The purpose of this study is to discuss briefly the biosynthesised bimetallic and core–shell NPs, their biomedical applications.Inspec keywords: nanofabrication, nanoparticles, biosensors, microorganisms, molecular biophysics, nanobiotechnologyOther keywords: biosynthesised bimetallic –shell, environmental friendliness, green synthesis, eco‐friendly efficient synthesis process, core–shell nanostructures, bimetallic –shell nanostructures, physiochemical methods, nanostructures synthesis, green physiochemical, NPs science, hybrid NPs, biomedical applications, core–shell nanoparticles, bimetallic –shell nanoparticles, biosynthesis     

Cytotoxicity,leishmanicidal, and antioxidant activity of biosynthesised zinc sulphide nanoparticles using Phoenix dactylifera

The synthesis of zinc sulphide nanoparticles (ZnS NPs) using a green approach was explored. The resulting nanoparticles (NPs) were characterised by UV–vis spectroscopy, scanning and transmission electron microscopy, X‐ray diffraction and Fourier transform infrared spectroscopy. The leishmanicidal, cytotoxic and antioxidant activity of the resulting synthesised ZnS NPs (<70 nm) were evaluated against Leishmania major (L. major) promastigotes and amastigotes by MTT assay and using a macrophage model. The ZnS NPs were able to counteract the effects of oxidative metabolites as demonstrated by the oxidant activity. The IC₅₀ value of butylated hydroxyanisole was 26.04 µg/ml as compared with the IC₅₀ for ZnS NPs (90.95 µg/ml). The NPs displayed no cytotoxicity for the murine macrophaghes as the selectivity index (SI) fell into the safety range (SI ≥ 10). These nanomaterials exhibited good antileishmanial activity against the L. major stages that were comparable to that of Glucantime, the drug of choice. The IC₅₀ values of ZnS NPs and Glucantime against amastigotes were 11.59 ± 2.51 and 4.95 ± 2.51 μg/ml, respectively. The IC₅₀ values for ZnS NPs and Glucantime versus promastigote were 29.81 ± 3.15 and 14.75 ± 4.05 μg/ml, respectively. Further investigation is essential to explore the biological effects of ZnS NPs on animal and/or clinical models.Inspec keywords: nanoparticles, nanofabrication, microorganisms, antibacterial activity, ultraviolet spectra, visible spectra, nanobiotechnology, X‐ray diffraction, Fourier transform infrared spectra, zinc compoundsOther keywords: cytotoxicity, leishmanicidal activity, antioxidant activity, biosynthesised zinc sulphide nanoparticles, Phoenix dactylifera, green approach, UV–vis spectroscopy, scanning electron microscopy, transmission electron microscopy, X‐ray diffraction, Fourier transform infrared spectroscopy, Leishmania major promastigotes, Leishmania major amastigotes, MTT assay, macrophage model, oxidative metabolites, butylated hydroxyanisole, murine macrophaghes, selectivity index, glucantime, ZnS     

A longitudinal study of the evolution of opinions about open access and its main features: a twitter sentiment analysis

Scientometrics - The present study aimed to explore how tweeters’ opinions about open access publishing and its main features evolved over time. Using a quantitative content analysis method...     

Diagnosing Parkinson's Disease Using Movement Signal Mapping by Neural Network and Classifier Modulation

Parkinson's disease is a growing and chronic movement disorder, and its diagnosis is difficult especially at the initial stages. In this paper, movement characteristics extracted by a computer using multilayer back propagation neural network mapping are converted to the symptoms of this disease. Then, modulation of three classifiers of C4.5, k‐nearest neighbors, and support vector machine with majority voting are applied to support experts in diagnosing the disease. The purpose of this study is to choose appropriate characteristics and increase the accuracy of the diagnosis. Experiments were performed to demonstrate the improvement of Parkinson's disease diagnosis using this method.     

How sustainable a scientifically developing country could be in its specialties? The case of Iran’s publications in SCI in the 21st century compared to 1980s

Investigating Iran’s scientific proficiency reflected in its scholarly outputs indexed in SCI during the 21st century and 1980s, the present study tries to propose the use of three features of science production including Specialty Diversity, Specialty Stability, and the growth of publications in the specialties, as the primary criteria in evaluating the contribution sustainability of a science system at macro level. They can be seen as the prerequisites every science system should realize to ensure a sustainable movement towards scientific development. The results reveal that Iran’s contributions had been not only limited in number in 1980s, but also exposed to serious subject fluctuations, so that a scarce number of the fields were found to be stable regarding Iranian contributions. Moreover, none of them had experienced a significant, exponential positive growth during the decade. The situation is incomparable to the 21st century where Iran’s contributions were as diversified as almost all of the SCI subject categories. It also reached long- or short-term stability in a majority of the categories. None of the previously stabilized specialties collapsed in the second 6-year sub-period. On the other hand, previously fluctuating fields mostly stabilized later. Moreover, a majority of the fields experienced significant exponential growths. Overall, according to the results, a developing science system might be characterized by its Specialty Diversity and Stability, as well as an annual growth in its publications in the specialties. Though meeting the criteria does not necessarily guarantee the achievement of quality standards, it may enhance the visibility of the contributions and thereby their recognition.