Using AC field measurement data at an arbitrary liftoff distance to size long surface-breaking cracks in ferrous metals

We propose a model-based inversion method to size long surface-breaking cracks in ferrous metals using alternative current field measurement (ACFM) data at an arbitrary liftoff distance. This method employs conjugate gradients optimization to invert measured surface ACFM signal to crack depth. To alleviate the adverse effect of sensor liftoff uncertainty on crack sizing, we propose a blind de-convolution algorithm for reconstructing respective surface ACFM crack signal. In this algorithm, the partially known filter function associated with the sensor liftoff is estimated from which the surface crack signal can be restored. The validity of the proposed inversion method is demonstrated by comparing the actual and predicted depths of several simulated and machine-made long cracks in mild steel test blocks.     

Interaction of hydrogen sulfide with the pristine and B&N-doped beryllium oxide nanotube: DFT study

ABSTRACT

In this study, hydrogen sulfide interaction with pristine, B-, N-, and B&N atom-doped beryllium oxide nanotube (BeONTs) is investigated by the density functional theory (DFT) method. At the first step, we considered different configuration models for the adsorption of H₂S on the surface of nanotube and then we selected 12 stable models for this study. The structures of all selected models are optimized and the quantum properties, thermodynamic parameters, natural bond orbitals (NBO), reduced density gradient (RDG), molecular electrostatic potential (MEP), and atom in molecule (AIM) parameters are calculated at the cam–B3LYP level of theory with 6–31G (d) base set. The obtained E_ads for the exterior surface of nanotube is exothermic and is in the range –3.15 to –28.34?Kcal mol^–1, and that for the interior surface is endothermic and is in the range 19.17 to 27.17?kcal mol^–1. The gap energy for pure, B-doped, N-doped, and B&N-doped BeONTs is 10.11, 10.03 (α spin), 10.13 (α spin), and 9.35?eV, respectively. The results of thermodynamic parameters, such as ΔG and ΔH values for the adsorption of H₂S, on the surface of B-doped BeONTs are more negative than other models and favorable in thermodynamic approach. The NBO, MEP, NMR, and HOMO–LUMO results confirm that the electron charge transfer occurs from H₂S molecule toward BeONTs, as a result the bonding type of H₂S?…?BeONTs is weak ionic.     

Application of Amine Modified Magnetic Nanoparticles as an Efficient and Reusable Nanofluid for Removal of Ba2+ in High Saline Waters

Silicon - This study describes an investigation on the application of functionalized nanoparticles used as a sorbent for extraction and removal of barium ions from high saline waters. Magnetic...     

Amygdalin Contents of Oil and Meal from Wild Almond: Effect of Different Heat Pretreatment and Extraction Methods

The effects of different heat treatment methods on the extraction yield of oil and the amygdalin contents of the wild almond meal and oil were investigated. When using hexane as a solvent for the extraction, oil yield and amygdalin contents of the extracted oils increased by increasing the applied temperature as the pretreatment (46.1–51.6%, w/w, for oil yield and 26–49 mg/100 mL oil for the amygdalin content). When using mechanical oil extraction, hot-press resulted in higher oil yield (23.2%) than did the cold-press (15.6%) but the amygdalin levels of the extracted oils were not significantly different (12.8–12.9 mg/100 mL oil). Autoclaving ground wild almond and hot-press resulted in a significant increase in the peroxide and acid values of the oils. Investigation of fatty acid profiles of different samples showed that heat treatment and extraction method in this study did not impact the fatty acid profiles of the extracted oils.     

Polymeric encapsulation of liquids via plasma surface polymerization

This study introduces a new approach of liquid encapsulation using an atmospheric pressure plasma (APP). The technique is similar to interfacial polymerization, though here one phase is liquid (that contains unsaturated C═C bonds) and the other phase is plasma (that contains free radicals). When combined, the atmospheric plasma can induce surface polymerization of an acrylate-based liquid, resulting in a thin polymeric skin on top of the liquid. Measurements with an atomic force microscope and a spectroscopic ellipsometer estimate the thickness of the skin formed on top of di(ethylene glycol) diacrylate to be 40–50 nm. To demonstrate an application of this method, we encapsulated hemispherical capsules of reactive adhesives on a glass substrate. These adhesives are based on thiol-acrylate and thiol-acrylate-epoxy systems that react in the presence of a strong base catalyst. Plasma-induced polymerization can encapsulate, immobilize, and isolate separate droplets of resin and the catalyst in a latent (nonreactive) state. These capsules remain latent until they rupture in response to physical contact. A tensile testing machine reports an adhesive strength of ~ 2 MPa for the formulated resins after curing. The capsules reported here may be useful for storing functional liquids for just-in-time release, such as contact-sensitive adhesives, on-demand lubricants, or self-healing agents. © 2020 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48880.     

A mobile robot mapping model inspired from the place cells functionality of hippocampus based on dimension reduction technique

ABSTRACT

In this paper, a new mobile robot mapping algorithm inspired from the functionality of hippocampus cells is presented. Place cells in hippocampus can store a map of the environment. This model fuses odometry and vision data based on dimensionality reduction technique, hierarchically. These two types of data are first fused and then considered as inputs to the place cell model. Place cells do the clustering of places. The proposed Place cell model has two types of inputs: Grid cells input and input from the lateral entorhinal cortex (LEC). The LEC is modelled based on the dimension reduction technique. Therefore, the data that causes locations different to be inserted into the place cell from this layer. Another contribution is proposing a new unsupervised dimension reduction method based on k-means. The method can find perpendicular independent dimensions. Also, the distance of cluster centres found in these dimensions is maximised. The method was compared with LDA and PCA in standard functions. Although LDA is a supervised method, the result showed that the proposed unsupervised method outperformed. To evaluate the place cells model, sequences of images collected by a mobile robot was used and similar results to real place cells achieved.     

Resource Management in a Peer to Peer Cloud Network for IoT

Wireless Personal Communications - Software-Defined Internet of Things (SDIoT) is defined as merging heterogeneous objects in a form of interaction among physical and virtual entities. Large scale...     

Reduction of carbon dioxide to methanol on the surface of adenine functionalized reduced graphene oxide at a low potential

In this study, the surface of reduced graphene oxide (rGO) was modified with adenine via diazonium reaction. Then, to prepare Pt@Adenine-rGO, Pt was deposited on the surface of adenine-rGO, using cyclic voltammetry in the range of ?0.30 to +1.30 V at a scan rate of 100 mV s^?1 in a solution containing Pt salt. Afterward, it was characterized by various techniques such as scanning electron microscopy, X-ray photoelectron spectroscopy, and infrared spectroscopy. Electrochemical studies showed the efficient electrocatalytic behavior of Pt@Adenine-rGO for the reduction of CO₂ to methanol at ?0.30 V. The products formed on the surface of Pt@Adenine-rGO were monitored using different techniques including Raman spectroscopy, gas chromatography, gas chromatography-mass spectrometry, and ¹³C NMR spectroscopy. Our findings indicated that methanol with a reasonably high Faradaic efficiency up to 85% and a current density of 0.5 mA cm^?2 as the main product of CO₂ reduction on the surface of Pt@Adenine-rGO.