Search

The global trend towards conscious consumption plays an important role in consumer preferences regarding both the composition and quality of food and packaging materials, including sustainable ones. The development of biodegradable active packaging materials could reduce both the negative impact on the environment due to a decrease in the use of oil-based plastics and the amount of synthetic preservatives. This review discusses relevant functional additives for improving the bioactivity of biopolymer-based films. Addition of plant, microbial, animal and organic nanoparticles into bio-based films is discussed. Changes in mechanical, transparency, water and oxygen barrier properties are reviewed. Since microbial and oxidative deterioration are the main causes of food spoilage, antimicrobial and antioxidant properties of natural additives are discussed, including perspective ones for the development of biodegradable active packaging. [ABSTRACT FROM AUTHOR]

The aim of the research was to modify the surface of construction textiles by means of the use of thin silver oxide films, investigate the structure and optical and mechanical properties, and determine the structure, optical and mechanical properties of the aged composites. Thin films of silver oxide (Ag2O) were synthesized on a flexible PET/PVC construction textile (CT); the structural, optical, and physical properties, as well as the effect of artificial aging on these properties, were investigated. The SILAR method (successive ionic layer adsorption and reaction) was used to synthesize thin Ag2O films on the CT surface. Before the thin films were deposited, the CT surface was mechanically roughened and pretreated with acidic and alkaline solutions at an elevated temperature. XRD analysis showed that the deposited films were a polycrystalline mixed phase material consisting of Ag2O, AgO, and metallic Ag. Diffuse reflectance spectra in the ultraviolet and visible ranges (UV-Vis) were used to study the optical properties of the deposited thin films. The synthesized Ag2O/CT composites were direct-gap semiconductors (the optical band gap (Eg) was 0.89 ± 0.02 eV). Eg and refractive indices (n) increased as the aging tests were carried out. Higher Eg and n meant that the composites were a good material for optoelectronic applications. The results showed that, after modification, the structural properties and tear strength of the PET/PVC fabric remained the same while the tensile strength decreased. The same tendencies remained after artificial aging. [ABSTRACT FROM AUTHOR]

The purpose of the article, to predict the actual content of teachers’ professional competencies that ensure the productive use of media and digital resources in solving pedagogical tasks, to propose ways to form such competencies by media means. With regard to the findings of the study, the following conclusions were made. A modern educator needs competencies related to the search and selection of media products and digital technologies for solving pedagogical tasks (orientation-constructive), designing an educational process that allows them to realize their pedagogical potential (design), organizing individual and group educational and cognitive activities of students in a virtual environment (organizational), pedagogical communication in a virtual environment (communicative), the use of media- and digital resources in the educational process, taking into account individual requests and special needs of students (inclusive), ensuring the safety of the media and digital resources used by the teacher and students (health-saving), continuous formation and self-development of digital and media literacy and culture (developing), creation of new pedagogical practices by means of integration of traditional, media- and digital means (innovative), ensuring the humanistic orientation of the process of using digital and media tools to solve pedagogical tasks (humanistic). To develop such competencies, it is necessary to involve media: cinema, educational video content, electronic educational resources, etc. [ABSTRACT FROM AUTHOR]

The article presents the results of studies of changes in the microstructure of the meat system as a whole and its protein component during freezing, subsequent defrosting, and storage of canned meat. Microstructural analysis of the prototypes showed the presence of several types of destruction of muscle fibers, loosening of collagen fiber bundles, and the formation of multiple cavities due to the action of ice crystals. The main components of sterilized canned meat had new characteristics after thawing, such as decreased transverse striations of muscle tissue fibers, loosening of myofibrils, changes in the size and shape of sarcomeres, violation of sarcolemma integrity, and multiple fiber fragmentation with the formation of a fine-grained protein mass. Freezing did not lead to a decrease in the content of the high-molecular-weight protein fraction of the nitrogen system, the ratio of the peptide fraction content to the residual nitrogen remained equal to 5.2. However, the ratio of non-protein nitrogen to total nitrogen decreased by 1.8 times due to the destruction of lowmolecular-weight nitrogen under the action of ice crystals. The dynamics of the eh values of control and experimental canned food samples during storage indicated the loss of oxidative stability of the protein system of the samples subjected to freezing. Based on the results, we would like to recommend that logistic organizations sort and confirm canned meat safety and quality requirements after thawing in the case of unforeseen circumstances. [ABSTRACT FROM AUTHOR]

The article substantiates the need for a humanitarian vector of studying the use of media and digital resources in education, addressing the phenomenon of the teacher’s potential to use such resources. The identified risks of inadequate realization of such potential are: risks related to misunderstanding by teachers of goals, values and meanings of the use of media and digital resources; the risks of reducing the creative component in the work of the teacher; the risks of overload and professional burnout of a teacher; risks to over–valuate the capacity of media and digital resources; risks of reducing the educational component and losing the orientation of the educational process. The conditions to reduce risks are revealed: formal and informal training of teachers, aimed at revealing the capacity of media and digital resources in achieving the goals of education and training that are significant for teachers; providing teachers with freedom to use such resources, the possibility of choosing both the content and methods of their application; time management for teachers, providing them with assistance from the administration in mastering new functions, stimulating a high level of self-organization; training teachers in the methods of integrating traditional and digital technologies in solving pedagogical problems, pedagogizing of the digital tools; identifying and implementing of educational opportunities and mastering the use of media and digital resources by the teacher; attracting students to create digital educational content, problematization of training; expanding the teacher’s understanding of the capacity of media and digital resources not only in solving pedagogical problems, but also in personal and professional self–improvement, overcoming professional difficulties. [ABSTRACT FROM AUTHOR]

Modern society is characterized by an increase in the volume of media resources available to children, which can have both positive and negative effects on socialization and the development of their personality. Media resources have a high pedagogical potential, but at the same time create strong competition for the teacher, and in case of unproductive use by children, the efforts of teachers are leveled. A problem arises: teachers do not fully utilize the pedagogical potential of media resources, do not select them purposefully, and students often use media resources unproductively. The purpose of this article is to systematically present the range of possible media resources for pedagogical use, the main directions, criteria and situations of their pedagogical monitoring, which will allow teachers to use them more productively in solving problems of training and education. Based on the results of the article, the following conclusions are made: in the current situation, the teacher needs to use a wide range of media resources (social networks, websites and thematic Internet resources, electronic learning tools, open online courses and educational platforms, school media, entertainment media resources). To identify their pedagogical potential and its productive use, teachers needs to carry out their pedagogical monitoring in three areas: monitorthe pedagogical potential of media resources, the possibilities of their use in solving problems of training, education and development; monitorthe effectiveness of the use of media resources by the teacher at the lesson and in extracurricular activities, of their impact on the results of training and education; monitor effectiveness of the use of media resources by students, including for self-education. [ABSTRACT FROM AUTHOR]

The article presents the potential of media material developmental as a set of cognitive, informational, communicative, axiological, hermeneutic, emotional, activity-related resources, the purposeful use of which by the teacher and students in the educational environment allows stimulating the intellectual, emotional, mental, moral development of students and ensures the improvement of the quality of the educational process. The main factors of the development media potential are identified: the content of the media material, the resources contained in it; methods and conditions (environmental factors) of the use of media in the educational process by the teacher; methods and conditions for the use of media in self-cognitive activity, self-education of students. In relation to the listed resources, the monitoring indicators of the media material are defined, which allow assessing the developmental potential both of its content and the process of use by the teacher and students. Indicators have been identified to assess: (1) the content of the media material; (2) the process of its use by the teacher for didactic and educational purposes; (3) the process of its use by students for independent cognitive activity and self-education. The proposed indicators can be used to select media content as a component of educational content in the creation of educational standards and programs, calendar and thematic planning, solving learning problems, assessing the quality of students' independent cognitive activity, the effectiveness of electronic and informational-educational environments, educational computer programs, electronic textbooks, etc. [ABSTRACT FROM AUTHOR]

PA6-Se-Cd composites were obtained by two-step assembly synthesis route. Firstly, a chemical bath deposition method was employed for preparation of PA6-Se precursors at room temperature using H2SeO3 and Na2SO3 solutions. These chalcogenized polymers further serve as proxies for cadmium selenide formation. The formation of CdSe is attained by exposing the PA6-Se precursor into a Cd(CH3COO)2 solution at different temperatures. The obtained composites were characterized by atomic absorption spectroscopy, optical microscopy and X-ray diffraction analysis. The Se consumption rate represents a global reaction system because it depends on the simultaneous occurrence of the heterogeneous reaction between Cd2+ ions and Se in the polyamide 6 (PA6) matrix and the selenium washout from polymer. The prepared PA6-Se-Cd composites are reproducible, uniform and pinhole-free. X-ray diffraction analysis showed the formation of cadmium selenide (CdSe) and selenium (Se8) phases with a hexagonal and a monoclinic unit cell, respectively. [ABSTRACT FROM AUTHOR]

Copper sulphide layers were deposited on the home-made polycarbonate (PC) plates by the chemical bath deposition (CBD) method. The layers were characterized by X-ray diffraction (XRD), optical microscopy (OM), Fourier transform infrared (FT-IR) spectroscopy. X-ray diffraction analysis showed that the layers are composed of covellite (CuS) and chalcocite (Cu2S) phases with a hexagonal and a monoclinic unit cell, respectively. The spherical particles of Cu2-xS with a size range of 1-27 μm in diameter were deposited depending on the number of deposition cycles. The room temperature sheet resistance of Cu2-xS layers deposited on PC plates is 1.13 kΩ/cm² after the fourth deposition cycle. [ABSTRACT FROM AUTHOR]

Thin films of Ag2S were deposited at room temperature on non-oriented isotactic polypropylene substrates immersed in a bath mixture containing aqueous solutions of silver nitrate, AgNO3, for silver ion source, sodium thiosulfate, Na2S2O3, for sulfide ion source and as a complexing agent, and nitric acid, HNO3, for pH adjustment. Film samples were characterised by X-ray photoelectron spectroscopy (XPS) and chemical analysis. XPS analysis confirmed that a layer of Ag2S was formed on the surface of the polypropylene film. The films were studied for their electrical conductivity and the results showed that the measured electrical sheet resistance depended on Ag : S ratio. A non-destructive millimeter wave analysis showed that distribution of Ag2S particles according to resistivity distribution on the PP samples area is homogenous. [ABSTRACT FROM AUTHOR]

Layers of silver sulfide, Ag2S, on the surface of polypropylene (PP) film were formed by the chemical bath deposition method (CBD). An initial treatment of PP with modifiers is required in order to provide the adherence to the polymer surface. Film samples were characterized by X-ray diffractometry (XRD), optical microscopy, scanning electron microscopy (SEM) / energy dispersive X-Ray (EDX) analysis and atomic force microscopy (AFM). XRD and EDX methods confirmed that on the surface of the polypropylene film a layer of silver sulfide was formed. The surface morphology, texture and uniformity of the silver sulfide layers formed on the PP surface depend on the number of polymer immersions into the precursor solution. The formation of silver sulfide layers proceeded irregularly in the form of islands which grew into larger agglomerates. [ABSTRACT FROM AUTHOR]

Silver sulphide, Ag2S, layers on the surface of polypropylene (PP) film was formed by chemical bath deposition method (CBD). Film samples were characterised by X-ray photoelectron spectroscopy (XPS), attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray diffraction analysis (XRD). The surface morphology, texture, and uniformity of the silver sulphide layers were formed on PP surface dependent on the number of polymer immersions in the precursor solution. XPS analysis confirmed that on the surface of the polypropylene film, a layer of Ag2S was formed. ATR-FTIR and FTIR spectra analysis showed that the surface of Ag2S layers is slightly oxidized. All prepared layers gave multiple XRD reflections, corresponding to monoclinic Ag2S (acanthite). The Ag2S layer on polypropylene was characterized as an Ag+ ion selective electrode in terms of potential response and detection limit. The electrode was also tested as an end-point electrode for argentometric titration of thiamine hydrochloride. [ABSTRACT FROM AUTHOR]