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In this work, the impact of the defect on the transmission of a mechanical wave in a periodic quasi-one-dimensional structure was investigated. The multilayer structure was made of PLA and air, while the defect layer was PNM-0.38PT with a significantly higher value of acoustic impedance in relation to the materials of the base structure. The influence of the position of the defect in the structure and its thickness was analysed. Transmission as a function of frequency was determined using the Transfer Matrix Method algorithm. The work showed the presence of band gaps in the analyzed structures. The influence of the symmetry of structures and substructures on the transmission of a mechanical wave was investigated. The influence of the number of layers with very low acoustic impedance (air) on the number of high transmission peaks with a small half-width was also demonstrated. [ABSTRACT FROM AUTHOR]

In one-dimensional phononic crystals, as a result of multiple destructive interferences of a mechanical wave, the phononic band gap phenomenon occurs, i.e., the lack of propagation of a wave of a given frequency through the structure due to internal reflections at the layer boundary and destructive interference. In dynamic phononic crystals, the incident monochromatic mechanical wave at the boundary of the media does not propagate according to Fresnel's relations, but is transformed into a wave spectrum, which affects the phononic properties of the examined structures and allows them to be dynamically controlled. The paper analyzes the transmission and influence of the frequency of changes in the properties of the elements of the finite phononic structure described by sinusoidal functions on the propagation of mechanical waves. [ABSTRACT FROM AUTHOR]

In this work, the influence of different cross-sections of meta-atoms and their distribution on the occurrence of local resonance regions in inter-meta-atomic spaces of finite phononic structures was investigated. Software based on the Mathematica package was designed and implemented using the finite difference algorithm in the time domain to simulate mechanical wave propagation in phononic structures. Then, for the recorded time series from the inter-meta-atomic spaces, resonant frequency distributions were determined using Fourier transforms, and an analysis of the differences in frequency distributions depending on the location of the inter-meta-atomic space was carried out. [ABSTRACT FROM AUTHOR]

Bamboo Ash is a safer and more sustainable building material. It is possible to use bamboo ash as a partial cement replacement as an alternative to cement application and also to reduce pollution. For this study, the main purpose is to determine the compressive strength and water absorption of cement sand brick containing bamboo ash. Laboratory tests such as compression tests and water absorption tests on cement sand brick with bamboo ash as a partial replacement for cement have been conducted. The mixes with various ratios using bamboo ash are 5%, 7%, and 10%. The specimen size for cement sand brick is 215 mm long, 102.5 mm wide, and 65 mm deep according to BS3921:1985. The results from the specimens containing Bamboo Ash have been compared to the control specimens. The water absorption test results increase as the percentage of Bamboo Ash increases due to particle size and air void, but the compressive strength decreases at 28 days. [ABSTRACT FROM AUTHOR]

The paper presents the results of tests on dynamic stability of Bernoulli-Euler beam with damages. Damages (cracks) were modeled using three rotational springs. An analysis of the influence of crack depth and their position relative to the beam ends on dynamic stability of the beam was carried out. The problem of dynamic stability was solved by applying the mode summation method. Applying an orthogonal condition of eigenfunctions, the dynamic of the system was described with the use of the Mathieu equation. The obtained equation allowed the dynamic stability of the tested system to be analyzed. Stable and unstable solutions were analyzed using the Strutt card. [ABSTRACT FROM AUTHOR]

This work concerns the study of the coatings for the ultrasound frequency range as a quasi one-dimensional phononic crystal structure protecting a sea object against high resolution active sonar in the frequency range most commonly found for this type of equipment. The topology of the examined structure was optimized to obtain a band gap in the 2.2-2.3 MHz frequency band. For this purpose, a genetic algorithm was used, which allows for optimal distribution of individual elements of the ultrasound multilayer composite. By optimal distribution is meant to achieve a structure that will allow minimal reflectance in a given frequency range without height reflectance peaks with a small half width. Analysis of the wave propagation was made using the Transfer Matrix Method (TMM). As part of the research, 15 and 20-layer structures with reflectance at the level of 0.23% and 0.18%, respectively, were obtained. Increasing the number of layers in the analyzed structures resulted in finding such a distribution in which a narrow band of low reflectance was obtained, such distributions could also be used as bandpass filters. The use of a genetic algorithm for designing allows to obtain modern coatings, the characteristics of which result from the structure. [ABSTRACT FROM AUTHOR]

The aim of this paper were studies of the structure and magnetic properties of the bulk Fe60Co10WxMo2Y8B20-x (x = 0, 1, 2) alloys. Ingots of the alloys were prepared by arc melting of high purity elements in an argon atmosphere. The samples in the form of plates were obtained by a rapid solidification of liquid metal in a copper mold cooled with water. Topography of produced samples were examined using a ZEISS SUPRA 35 high resolution scanning electron microscope. Furthermore, using a vibrating sample magnetometer the magnetization in high magnetic fields was studied. Moreover, from initial magnetization curves the parameters related with the Holstein-Primako- paraprocess were determined. [ABSTRACT FROM AUTHOR]

This paper presents the results of studies on the magnetic properties of the Fe60Co10Mo2Y8B20 alloy. The samples were fabricated in the form of plates by the injection-casting method. The structure of the investigated alloy, in the as-quenched state and after annealing, was verified by using X-ray diffractometry. The magnetization curves as a function of temperature were measured by a force magnetometer. From thermomagnetic curves the Curie temperature of the alloy was determined. As a critical parameter β was chosen to be equal to 0.36 for these calculations, it confirmed that the alloys may be considered as ferromagnetic of the Heisenberg type. Additionally, using a vibrating sample magnetometer the magnetization and coercivity field were studied (in magnetic field up to 2 T). [ABSTRACT FROM AUTHOR]

Childhood obesity has reached epidemic levels worldwide. Overweight and obesity is associated with an increase in several inflammatory markers, leading to chronic low-grade inflammation responsible for macro- and microvascular dysfunction. While the impact of obesity on overall health is well-described, less is known about its ocular manifestations. Still, there are few studies in children and adolescents in this regard and they are inconsistent. However, some evidence suggests a significant role of overnutrition in the development of changes in retinal microvasculature parameters (wider venules, narrower arterioles, lower arteriovenous ratio). Higher values of intraocular pressure were found to be positively correlated with high body mass index (BMI) as well as obesity. In addition, the retinal nerve fiber layer (RNFL) values seem to be lower in obese children, and there is a significant negative correlation between RNFL values and anthropometric and/or metabolic parameters. Changes also could be present in macular retinal thickness and choroidal thickness as well as in the retinal vessel density in children with obesity. However, these associations were not consistently documented. The purpose of this review is to present the most current issues on child obesity and the related potential ocular effects through an overview of international publications from the years 1992-2022., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© 2023 Dezor-Garus, Niechciał, Kędzia and Gotz-Więckowska.)

A provincial focus on immigration and improved foreign credential recognition has led to an investigation of best practices and subsequent recommendations for the development and implementation of a sustainable university-based bridging program for internationally educated dietitians in Atlantic Canada. Data were collected from various sources and used to inform program decisions and direction. An advisory framework was established through a core group representing dietetics education and regulation and internationalization. Subsequently, a key stakeholder group was formed. As a result of this collaboration and research, a dietetics bridging framework was developed and a program pilot tested. Lessons learned may inform similar endeavours and highlight the importance of collaborative leadership and collaboration among multiple stakeholders, and of creatively addressing program sustainability issues while keeping learners (internationally educated dietitians) at the centre.