Oxidation States and the Acidity of Ordered Arrays of Co–Pb Mixed Oxide Nanoparticles Templated in SBA15

Co, Pb and CoPb containing SBA15 mesoporous materials were prepared by direct synthesis method. When Co and Pb were loaded simultaneously, nanoparticles were formed in the channels of SBA15 as observed by transmission electron microscopy. These nanoparticles blocked the pores and decreased the apparent surface areas indicated by BET analysis. Pyridine adsorption on these catalysts revealed that while monometallic additions did not influence the overall acidity of SBA15, in the bimetallic system, characteristic bands due to pyridine adsorption on Co²⁺ ions were observed.     

A study on the effects of different gums on dielectric properties and quality of breads baked in infrared-microwave combination oven

In this study, the effects of different gums on dielectric properties of doughs and breads baked in infrared-microwave combination oven were investigated. In addition, the quality parameters of breads formulated with different gums baked in infrared-microwave combination oven were determined. The gums used were xanthan, guar, xanthan-guar blend and κ-carrageenan. The gums were added to the formulation at 0.5% concentration. The dielectric properties and quality parameters of breads baked in infrared-microwave combination oven were found to be dependent on gum type. κ-carrageenan resulted in undesirable final bread quality, while xanthan-guar blend addition improved bread quality (high specific volume and porosity, low hardness values). The dielectric properties of bread samples formulated with κ-carrageenan were found to be the highest among the other gum types.     

Effects of infill walls on base responses and roof drift of reinforced concrete buildings under time‐history loading

In this study, the effects of infill walls on base reaction and roof drift of reinforced concrete frames were investigated. These effects were studied using 3D finite element method on 216 building models. Number of floors, number of bays, ratio of shear walls and ratio of infilled bays were selected as parameters. Sensitivity analysis was performed to determine the effect of each parameter on base shear, normal base reaction and roof drift. Based on the sensitivity analysis, the percentage of shear walls was the most important parameter affecting base shear, normal base reaction and roof drift. The effect of infill walls on base shear, normal base reaction and roof drift decreased when the percentage of the shear walls increased. The models without any infill walls had minimal normal base reaction under time‐history loading. However, an increase in the percentage of infill walls led to an increase in normal base reaction. The roof drift of the models was not critical. Copyright © 2009 John Wiley & Sons, Ltd.     

Mixed levels of coarse-graining of large proteins using elastic network model succeeds in extracting the slowest motions

We perform a mixed coarse-graining approach in a normal mode analysis of protein motions, which enables the modeling of a protein's native conformation with different regions having low and high resolution. As a result, the dynamics of the interesting functional parts within a supramolecular assemblage can be analyzed at high resolution, while the remainder of the structure is represented at poorer resolution, thus keeping the total number of nodes in the system sufficiently low for computational tractability. Our results indicate that the vibrational dynamics of specific components in a large multi-subunit protein are best described by retaining all the components of the structure, whether at higher or lower resolution. It is also shown that similar frequency distributions are obtained for different proteins and at different levels of coarse-graining, at the lower end of the spectrum, where the most significant slowest motions occur.     

A computational and experimental approach to develop minocycline-imprinted hydrogels and determination of their drug delivery performances

In this study, minocycline-imprinted hydrogels are developed for controlled drug delivery in ocular disease treatments. An integrated computational and experimental study are conducted for investigating the relationship between design parameters and the drug loading/release performance of hydrogels. First, suitable functional monomers are determined for successful drug-imprinting by studying pre-polymerization conditions with full-atom molecular dynamics (MD) simulations. MD simulations suggest that acrylic acid and itaconic acid are suitable monomers for imprinting minocycline. Then, minocycline-imprinted hydrogels are synthesized with acrylic acid, commonly used in hydrogels, and three different amounts of cross-linker ethylene glycol dimethacrylate, 1, 2 and 3 mol%. All hydrogels are characterized and their drug loading and release performances are determined. Our computational and experimental calculations indicate an optimum cross-linker amount of 2 mol% for controlled minocycline release from imprinted hydrogels with an imprinting factor of almost 3. Finally, the drug release kinetics are determined by Korsmeyer-Peppas model.     

One-step electrochemical preparation of ternary phthalocyanine/acid-activated multiwalled carbon nanotube/polypyrrole-based electrodes and their supercapacitor applications

In the present work, we report one-step preparation of phthalocyanine/acid-activated multiwalled carbon nanotube/polypyrrole modified pencil graphite electrodes (Pc/AA-MWCNT/PPy/PGE) for electrochemical supercapacitor applications. Conducting polymer-based ternary electrode materials were prepared by in situ electropolymerization of pyrrole in the presence of AA-MWCNT and Pc. The structures of prepared electrodes were characterized by different techniques such as Fourier transform infrared, scanning electron microscopy, energy-dispersive spectrometer, atomic force microscope, Brunauer-Emmett-Teller, cyclic voltammetry, and electrochemical impedance spectroscopy to examine their structural and electrochemical properties. This study examines for the first time supercapacitive properties of ZnPc/AA-MWCNT/PPy/PGE and CuPc/AA-MWCNT/PPy/PGE. The specific capacitances of electrodes have been found as 304 F/g for CuPc/AA-MWCNT/PPy/PGE and 117 F/g ZnPc/AA-MWCNT/PPy/PGE with 10 A/g charge-discharge current densities. When compared to all preparation electrode materials in the literature, CuPc/AA-MWCNT/PPy/PGE exhibited superior supercapacitive behavior. The synergistic effect of PPy, AA-MWCNT, and Pc with excellent physical interface presents better charge storage capacity and less charge transfer resistance. We observed that the Pc/AA-MWCNT/PPy/PGE electrodes can synergistically improve the charge storage property in comparison to its individual constituents.     

Hydrophobically modified nanocomposite hydrogels with self-healing ability

Several strategies have been developed in the past two decades to increase the mechanical performance of the hydrogels, and to generate self-healing function within the polymer network. Here, we combine two of these strategies to create hydrophobically modified nanocomposite (NC) hydrogels with high mechanical strength and self-healing efficiency. The hydrogels were prepared by in situ copolymerization of N,N-dimethylacrylamide and n-octadecyl acrylate (C18A) in the presence of 2 w/v % Laponite clay nanoparticles in an aqueous solution of worm-like sodium dodecyl sulfate micelles. Incorporation of hydrophobic C18A segments into the gel network significantly increases both the storage and loss moduli of NC hydrogels indicating increasing elasticity and energy dissipation. An improvement in the mechanical performance and self-recoverability of NC hydrogels was also observed after hydrophobic modification. The compressive fracture stress and Young's modulus increase with increasing amount of C18A, and they become 9 ± 1 MPa and 30 ± 2 kPa, respectively, at 4 mol % C18A. Incorporation of hydrophobic segments also provides a larger energy dissipation under large strain as compared to the traditional NC hydrogels providing a self-healing efficiency of 90 ± 10% in mechanically strong NC hydrogels. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48853.     

A new approach for data stream classification: unsupervised feature representational online sequential extreme learning machine

Multimedia Tools and Applications - The characteristics of the data stream have brought enormous challenges to classification algorithms. Concept drift is the most concerning characteristics, and...     

Agent-based modelling and construction – reconstructing antiquity’s largest infrastructure project

Archaeological remains around the world are testament that large-scale construction projects have been successfully carried out for millennia. This success is particularly evident through the great infrastructural works of the Roman Empire. Yet, it was when the capital was moved from Rome to Constantinople that the largest of these projects was undertaken. This megaproject of the fourth- and fifth-century water supply was made of hundreds of kilometres aqueduct channels and bridges that brought fresh water to the city’s complex system of reservoirs and cisterns. Unlike projects of the previous centuries, we are left with no written record of how this titanic project was undertaken and existing archaeological and historical commentaries on structures of this period do not provide details of organization of construction. We explore the nature of building Constantinople’s water supply through diverse sources of knowledge and the application of agent-based modelling – a method for simulating the actions, interactions and behaviours of autonomous agents and the resulting emergent properties of the system in which they are a part. This paper demonstrates the ability of ABM to develop and test richer hypotheses about historical construction organization and management than physical and historical evidence on their own.