Multipole Born series approach to light scattering by Mie-resonant nanoparticle structures

Exciting optical effects such as polarization control, imaging, and holography were demonstrated at the nanoscale using the complex and irregular structures of nanoparticles with the multipole Mie-resonances in the optical range. The optical response of such particles can be simulated either by full wave numerical simulations or by the widely used analytical coupled multipole method (CMM), however, an analytical solution in the framework of CMM can be obtained only in a limited number of cases. In this paper, a modification of the CMM in the framework of the Born series and its applicability for simulation of light scattering by finite nanosphere structures, maintaining both dipole and quadrupole resonances, are investigated. The Born approximation simplifies an analytical consideration of various systems and helps shed light on physical processes ongoing in that systems. Using Mie theory and Green’s functions approach, we analytically formulate the rigorous coupled dipole-quadrupole equations and their solution in the different-order Born approximations. We analyze in detail the resonant scattering by dielectric nanosphere structures such as dimer and ring to obtain the convergence conditions of the Born series and investigate how the physical characteristics such as absorption in particles, type of multipole resonance, and geometry of ensemble influence the convergence of Born series and its accuracy.

Methods for detecting and correcting errors in irregular structures under the influence of heavy charged particles

The paper considers methods of increasing the durability of radio-electronic equipment in space, namely, methods of detecting and correcting errors during the action of the HCP. Currently, redundancy methods are used to ensure durability, when two or three processors work in parallel in the system, and a special node compares the results of their work. If the results do not match, an error signal will be generated, and the system will begin to perform actions to correct it. The article describes and classifies the main circuit, structural-functional, algorithmic methods for detecting and correcting errors. It is shown that circuit solutions lead to an increase in the crystal area. Therefore, the problem arises of ensuring radiation resistance with a minimum increase in the crystal area.

Microencapsulation of Brazilian Cherokee blackberry extract by freeze-drying using maltodextrin, gum Arabic, and pectin as carrier materials

There are many blackberry cultivars in Brazil; however, the characteristics and applications of the Cherokee cultivar have not yet been widely studied. For this reason, this research investigated the behaviour of maltodextrin (MD), gum Arabic (GA), and pectin (PEC), as carriers combined in different proportions (20% MD, 15% MD + 5% GA, 15% MD + 5% PEC), on encapsulation of Cherokee blackberry pulp extract obtained by freeze-drying. The results of moisture content (2.73-3.36%), water activity (aw) (0.11–0.15), solubility (52.40–54.11%), hygroscopicity (17.59–21.11%), colour (hue 0.24–0.32), retention of anthocyanins (51.55–60.53%), total phenolic compounds (39.72–70.73 mg GAE/100g), antioxidant activity at 25 mg/mL (77.89–80.02%), IC50 (12.26–14.53), simulated in vitro digestion and morphology were discussed. Concerning morphology, blackberry powders had irregular structures and amorphous structures. Comparatively, the best results were obtained for MD-GA. MD-GA presented the highest content of phenolic compounds (70.73 ± 1.84 mg GAE/100g) and antioxidant activity (80.02%), as well as the lowest IC50 value (12.26). In general, all powders showed an increase in phenolic compounds during in vitro digestion, because of the pH conditions and digestive enzymes present in the simulated digestive fluid. This result shows that the wall material provides protection, since the blackberry rich extract (RE) showed degradation of phenolic compounds in in vitro digestion. In this sense, freeze-drying is a suitable technique for the encapsulation of Cherokee blackberry pulp extract.

Examination of Structures Built with Tunnel Formwork in Terms of Strength and Cost according to the Earthquake Regulations of 2007 and 2018

Turkey has always been exposed to active fault lines passing through and unpredictable seismic activities. These ground movements have always been one of the important issues in our country, which have led to great destruction and loss of lives and property in its past. For this reason, our earthquake regulations, which aim to design more accurately against earthquake movements, are continuously made improvements. In this study, the analysis of structures built with tunnel formwork system which is popular today with the new earthquake regulations entered into force in 2018, and the strength and cost according to the old earthquake regulation in terms of what differences will occur. In addition to the study, we investigated how the number of floors and regular floor plans affects the results. For this purpose, two types of structures were covered with 5, 10, and 15 storey models created, first in the 2007 earthquake regulation; then, in the 2018 earthquake regulation, design analysis was carried out. As a result, the new earthquake regulation, which came into force in 2018, led to more realistic results as it provides more accurate environmental inputs used in design analysis. Earthquake loads affecting floors increased by 3.9% for 5 storey in regular structures, decreasing by 38.4% for 10 stories and 43.3% for 15 stories. More irregular structures increased 7.3% for 5 storey, 10-storey structures decreased by 38.9%, and 15-storey structures decreased by 43.6%. In terms of cost, there was a 0.07% increase in total cost in 5-storey buildings, 2.45% in 10-storey buildings, and a 3.91% reduction in 15-storey buildings. In addition to these results, an empirical formula that estimates m2 prices depending on the number of floors was obtained.

Quantitative Assessment of Chirality of Protein Secondary Structures and Phenylalanine Peptide Nanotubes

In this study we consider the features of spatial-structure formation in proteins and their application in bioengineering. Methods for the quantitative assessment of the chirality of regular helical and irregular structures of proteins are presented. The features of self-assembly of phenylalanine (F) into peptide nanotubes (PNT), which form helices of different chirality, are also analyzed. A method is proposed for calculating the magnitude and sign of the chirality of helix-like peptide nanotubes using a sequence of vectors for the dipole moments of individual peptides.

Evaluation of the secondary structure of poly-γ-glutamic acid produced by Bacillus subtilis EGP5QL12 by circular dichroism spectroscopy method

An extracellular polymer was isolated from the culture liquid of Bacillus subtilis EGP5QL12 with the yield of 5,6 g/L. On the basis of the data of thin layer chromatography, colorimetric analyses and FTIR spectroscopy, it was established that the polymer is poly-γ- glutamic acid (PGA). PGA is widely used in medicine, cosmetology and the food industry due to its ability to bind water and metal ions. To assess the biotechnological potential of the isolated polymer and predict the possibilities of its application in various fields of the national economy, it is necessary to analyze the characteristic spectral features that make it possible to establish its secondary structure. The isolated PGA preparation was analyzed by circular dichroism spectroscopy at various pH values. According to the results of this study, it was found that the polymer forms predominantly β-structures with a low proportion of irregular structures and α-helices, which gives it a high potential for creating hydrogels and composite materials.

A Multi-Zoned Self-Resistance Electric Heating Method for Curing Irregular Fiber Reinforced Composite Parts

Fibre Reinforced Polymers (FRP) have been widely applied in various industries due to their outstanding properties. As a promising curing technology for FRP parts, the self-resistance electric (SRE) heating method has attracted plenty of attention. However, it is difficult for the SRE heating method to uniformly cure the FRP parts with irregular structures. In this paper, a multi-zoned SRE heating method is proposed, in which the FRP part is divided into several heating zones and the temperature of each zone is regulated independently. A multi-channel electrical voltage control system is developed to realise the multi-zoned SRE heating of a wing-shaped FRP part, in which a rapid zone-based temperature control responsiveness is achieved, and the maximum temperature difference is reduced from 60 °C to less than 10 °C, reaching 2.5 °C at its best. This work presents an alternative for the high efficiency and energy-saving curing process of FRP parts.

Seismic Response of Vertical Irregular Structures in Setback and Stepped Buildings

Vertical irregular buildings are frequently constructed across the globe for functional as well as aesthetic purpose. However post-earthquake reconnaissance survey reports revealed high seismic vulnerability of the building with vertical irregularities. Consequently it is very important to explore the reason behind the high seismic vulnerability and the poor performance of irregular structures during the earthquake. A humble effort is under taken considering several case studies comprising different configuration of vertical irregular structures, so as to comprehend the seismic behavior of vertical irregular structure using response spectrum and pushover analysis has been attempted in finite element software ETABS 16.2.1 version. The results of the analysis indicate the irregular structures have ample chance of higher stress concentration as well as higher displacement demand at the vicinity of irregularity. Member strength enhancement at the vicinity of vertical irregularity may improve the overall seismic performance of the building. Also, this research checks the adequacy of fundamental mode properties for the quantification of vertical irregularity. Furthermore, pushover analysis has been done to observe the hinge formation pattern and also the plastic hinge rotation for observing the performance level of building.