A robust SMES controller strategy for mitigating power and voltage fluctuations of grid-connected hybrid PV–wind generation systems

Electrical Engineering - Recently, hybrid generation systems (HGSs) are considered to be the optimal solution for supplying remote areas with the required electrical power. HGSs contain two or more...     

What does MIS survey research reveal about diversity and representativeness in the MIS field? A content analysis approach

Scientometrics - Diversity and representativeness are two enriching components of an academic field and for quite some time, Management Information Systems (MIS) researchers have been advocating...     

Microstructural,Thermal, Crystallization,and Water Absorption Properties of Films Prepared from Never-Dried and Freeze-Dried Cellulose Nanocrystals

In this paper, the microstructural, optical, thermal, crystallization, and water absorption properties of films prepared from never-dried (ND) and freeze-dried (FD) cellulose nanocrystals (CNCs) are reported. Morphology of the ND CNCs reveals a needle-like structure, while after freeze-drying, they show a flake-like morphology. Microstructural analysis of ND and FD CNCs are further studied via small angle X-ray scattering to probe interactions. ND CNCs yield a transparent film with a low surface roughness (14 ± 4 nm), while the FD CNC film evidence a significant reduction of their transparency due to their higher surface roughness (134 ± 20 nm). Although Fourier transform infrared spectroscopy and energy-dispersive X-ray spectroscopy analyses reveal no chemical change occurs during the freeze-drying process, yet a more intense thermal degradation profile is observed for FD CNC film, probably due to the higher oxygen ingress within the gaps created between the stacked flakes. This, in turn, results in a greater loss of crystallinity at a higher temperature (300 °C) compared to the ND CNC film. A rapid decrease in water contact angle of the FD CNC film proves that the morphology of flakes and their orientation within the film has a strong influence in increasing water absorption capacity.     

Botryticidal Activity of Nanosized Silver‐Chitosan Composite and Its Application for the Control of Gray Mold in Strawberry

Botrytis cinerea Pers, the gray mold fungus, is among the most dangerous plant pathogens that cause great losses in agricultural crops. The botryticidal activities of nanosized silver (nano Ag), fungal chitosan (CTS) irradiated fungal chitosan (IrCTS), and nano Ag‐IrCTS composite were investigated. All of the examined materials exhibited powerful antifungal activity against B. cinerea. The most effective compound was nano Ag‐IrCTS composite with a minimal inhibitory concentration of 125 μg/mL. The microscopic examination, of treated B. cinerea with the composite, revealed that an obvious alteration in mycelial shape was appeared accompanied and moderate lysis in fungal hyphae. With the prolongation of treatment, most of the fungal mycelia were lysed into small and elastic fragments. The consequence of strawberries coating, with antifungal composite based solution, was the disappearance of gray mold infection signs in 90% of the contaminated fruits after 7 d of storage, treated fruits had a fresh‐like appearance at the end of storage. Coating with nano Ag‐IrCTS solution could be highly recommended regarding its efficiency in prohibiting B. cinerea growth, preventing gray mold decay and enhancing the overall quality of coated strawberry fruits.     

Non linear dynamics of memristor based 3rd order oscillatory system

In this paper, we report for the first time the nonlinear dynamics of three memristor based phase shift oscillators, and consider them as a plausible solution for the realization of parametric oscillation as an autonomous linear time variant system. Sustained oscillation is reported through oscillating resistance while time dependent poles are present. The memristor based phase shift oscillator is explored further by varying the parameters so as to present the resistance of the memristor as a time varying parameter, thus potentially eliminating the need of external periodic forces in order for it to oscillate. Multi memristors, used simultaneously with similar and different parameters, are investigated in this paper. Mathematical formulas for analyzing such oscillators are verified with simulation results and are found to be in good agreement.     

Fractional-Order RC and RL Circuits

This paper is a step forward to generalize the fundamentals of the conventional RC and RL circuits in fractional-order sense. The effect of fractional orders is the key factor for extra freedom, more flexibility, and novelty. The conditions for RC and RL circuits to act as pure imaginary impedances are derived, which are unrealizable in the conventional case. In addition, the sensitivity analyses of the magnitude and phase response with respect to all parameters showing the locations of these critical values are discussed. A?qualitative revision for the fractional RC and RL circuits in the frequency domain is provided. Numerical and PSpice simulations are included to validate this study     

Formulation and characterization of glass–ceramics based on Na2Ca2Si3O9–Ca5(PO4)3F–Mg2SiO4-system in relation to their biological activity

Glasses having a chemical composition based on combeite [Na₂Ca₂Si₃O₉]–fluoroapatite [Ca₅(PO₄)₃F] and forsterite [Mg₂SiO₄] system were crystallized through controlled heat-treatment. Two forms of sodium calcium silicate e.g. combeite Na₂Ca₂Si₃O₉ and pectolite Na₂CaSi₃O₈, were formed together with diopside (CaMgSi₂O₆) and monticellite (CaMgSiO₄) in addition to fluoroapatite (Ca₅(PO₄)₃F) phases by thermal treatment of the glasses. Selected glass–ceramics were exposed to a simulated body fluid solution (SBF) which is close to human plasma for 3 weeks. Energy dispersive X-ray analysis (EDX) and inductive coupled plasma (ICP) analysis confirmed the formation of an apatite layer which indicate bioactivity in the all crystallized sample. A decreasing of surface bioactivity with increasing Mg₂SiO₄/Na₂Ca₂Si₃O₉ replacement was observed as indicated by the decrease in the amount of apatite layer on the surface of the crystallized specimens. The Vicker’s microhardness of the studied glass–ceramic materials are between 5,047 and 6,781 MPa.     

Correction: Novel Surface Topography and Microhardness Characterization of Laser Clad Layer on TC4 Titanium Alloy Using Laser-Induced Breakdown Spectroscopy and Machine Learning

Metallurgical and Materials Transactions A -     

Composition,anti-inflammatory,and antioxidant activities of avocado oil obtained from Duke and Fuerte cultivars

Avocado (Persea americana Mill.) fruit and oil are traditionally used for their antioxidant, anti-inflammatory and anti-aging properties. We investigated chemical variability between two avocado cultivars (Duke and Fuerte) in relation to their antioxidant and anti-inflammatory activities. Duke cultivar showed higher β-carotene and α-tocopherol content but significantly lower lipid content (36% dry weight) compared to Fuerte (52% dry weight). The ethanolic extract of Duke cultivar showed good antioxidant properties in 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay with IC₅₀ at 27.21 μg/ml, while that of Fuerte showed weak activity. Meanwhile, in rat paw edema anti-inflammatory model, Duke oil (15 mg/kg) was slightly more effective in reducing inflammation by 41.12% after 1 h compared to Fuerte oil (15 mg/kg). However, after 4 h, both oils showed comparable inhibition of edema by 35.39% and 34.14% (15 mg/kg). The study underscores that variability in chemical composition of different avocado cultivars could affect biological activities attributed to the fruit and its oil.