Natural Element Research Articles

Водата като концептуален и изобразителен материал в съвременните визуални изкуства

Water is an essential natural element, a diverse form with a social character, semantically upgraded in historical and cultural aspects. Its aggregate states are part of its semiotic and abstract construction, reflecting on the artwork of authors in the field of contemporary visual arts. The research is aimed at considering and discussing various works, the realization of which is related to different states of water as a pictorial and conceptually related material.

Free Vibration Analysis of Functionally Graded Sandwich Plates with a Homogeneous Core

The functionally graded (FG) sandwich plate has attained much attention in recent years due to its potential for exhibiting the merits of sandwich construction and FGM. Accordingly, intensive studies have focused on FG sandwich plates to investigate their mechanical behaviors. However, these mechanical behaviors are still in need of further investigation, particularly with respect to the major parameters. In this context, this paper intends to parametrically investigate the free-vibration behavior of the FG sandwich plate with a homogeneous core by developing a reliable and effective numerical method. This numerical method was based on hierarchical models, developed from the spectral model accuracy, and the 2-D natural element method (NEM). The hierarchical models were derived from the 3-D elasticity and the NEM was characterized by high smooth interpolation functions. From the verification experiments, the proposed method shows a good agreement with the reference and a uniform convergence to the 3-D elasticity. The free vibration characteristics of FG sandwich plates with a homogeneous core were investigated using the proposed numerical method. It was found that the calibrated fundamental frequency was significantly influenced by the type of material composing the core, the volume fraction index, the relative thickness and position of core layer, and the plate aspect ratio.

Lanthanum Chloride Induces Axon Abnormality Through LKB1-MARK2 and LKB1-STK25-GM130 Signaling Pathways.

Lanthanum (La) is a natural rare-earth element that can damage the central nervous system and impair learning and memory. However, its neurotoxic mechanism remains unclear. In this study, adult female rats were divided into 4 groups and given distilled water solution containing 0%, 0.125%, 0.25%, and 0.5% LaCl3, respectively, and this was done from conception to the end of the location. Their offspring rats were used to establish animal models to investigate LaCl3 neurotoxicity. Primary neurons cultured in vitro were treated with LaCl3 and infected with LKB1 overexpression lentivirus. The results showed that LaCl3 exposure resulted in abnormal axons in the hippocampus and primary cultured neurons. LaCl3 reduced the expression of LKB1, p-LKB1, STRAD and MO25 proteins, and directly or indirectly affected the expression of LKB1, leading to decreased activity of LKB1-MARK2 and LKB1-STK25-GM130 pathways. This study indicated that LaCl3 exposure could interfere with the normal effects of LKB1 in the brain and downregulate LKB1-MARK2 and LKB1-STK25-GM130 signaling pathways, resulting in abnormal axon in offspring rats.

IMPROVING THE QUALITY OF MAGNESIUM-SOLUBLE BIOLOGICAL ALLOY FOR IMPLANTS

Formulation of the problem. Currently, biosoluble materials are widely used for the manufacture of implants, among which the most promising are magnesium alloys. Magnesium is a natural element of the body. It is contained in bone and muscle tissue and involved in various metabolic processes. In addition, magnesium and its biocorrosion products have excellent biocompatibility. The main advantage of magnesium alloys is the positive effect magnesium has on the human body, but their quality is not satisfactory for use in the human body. Improved refining and modification processes of liquid melt can increase the properties of magnesium alloys. Purpose of research: to investigate and test various carbonaceous materials for refining and modifying magnesium melt. Method. Optical microscopy, application of standard techniques for determining the mechanical properties of magnesium alloy and special techniques for determining the refining and modifying ability of various carbon-containing materials. Results. The technology of cast magnesium alloys modification for Mg – Zr − Nd system by dispersed graphite powder is proposed. It is shown that the optimal carbon additive in the quantity of 0,05…0,1 % improves the mechanical properties due to grain grinding and additional strengthening of structural components. A complex filter containing equal quantity of magnesite, graphite and limestone is proposed. It provides an increased level of melt refining to obtain high quality casting. It is shown that the use of a complex carbon-containing filter provides not only efficient melt refining, but also its additional modification. In alloy structure the increased quantity of intermetallic γ-phase is observed, that provides increase the microhardness of alloy structural components and promotes increase of its physical-mechanical characteristics. Scientific novelty. The structure and properties of cast magnesium alloy for Mg –Zr – Nd system during modification with dispersed graphite powder and its filtration through carbon-containing materials are investigated. Practical significance. The developed complex technology for processing the liquid melt of magnesium alloys for the Mg – Zr − Nd system allows to increase the yield of suitable casting and improve its quality.

THE FIRE IN THE STRUCTURE OF THE DYNAMIC VISUAL COMMUNICATION: THE METHODS OF IMAGE CREATION

The modern person lives in the constant flow of visual messages and images that make their identification and perception more complicated. Against this background the actual issue is to search the ways of focusing on the certain information and attracting people’s attention due to the outrageous images creation. One of such ways is the implementation of the natural fire element into the design objects structure. The live fire as the contradictory meaningful image of the destruction and creation becomes the innovative means of visual language that activates the sensitive experience of the world cognition. In this regard, such huge changes in the visual communication design require the system analysis of the theory and practice of the integrated design systems, which are based on the physico-chemical properties of natural elements, especially fire.

Dirac Operators for the Dunkl Angular Momentum Algebra

We define a family of Dirac operators for the Dunkl angular momentum algebra depending on certain central elements of the group algebra of the Pin cover of the Weyl group inherent to the rational Cherednik algebra. We prove an analogue of Vogan's conjecture for this family of operators and use this to show that the Dirac cohomology, when non-zero, determines the central character of representations of the angular momentum algebra. Furthermore, interpreting this algebra in the framework of (deformed) Howe dualities, we show that the natural Dirac element we define yields, up to scalars, a square root of the angular part of the Calogero-Moser Hamiltonian.

The Importance of the Mediterranean in the Syro-Mesopotamian Kingdom of Mari in the Amorite Period

ABSTRACT Since the dawn of Mesopotamian history, the Mediterranean Sea has been considered a natural frontier, both feared and admired as the Great Sea. With the settlement of the Amorites in Mesopotamia, whose cradle was thought of as the “Land of the Sea,” that is, the Mediterranean shore, the importance of this natural element became notorious. The voyages of the sovereigns of the Amorite Syro-Mesopotamian kingdom of Mari—Yahdun-Lim, Samsi-Addu, and Zimri-Lim—to the Mediterranean coast, which this article analyzes in detail, attest to this importance. These journeys were previously studied by Abraham Malamat, among others. But due to the absence of a monumental record to attest to the displacement of Zimri-Lim, the importance of the latter as well as the connection between them have not been thoroughly examined. This article does so.

Methodology for Understanding Soil Erosion

This article aims to propose teaching educational techniques that support the understanding of soil erosion and the importance of soil conservation. This port, soil as it is an important natural element that permeates our daily lives, whether through the supply of food, as in the purity of surface and underground waters. In this way, providing educational techniques associated with Soil Education becomes relevant. With this, we provide, through didactic illustrations, to provide this understanding so that it can be improved and disseminated to the academic and school community.

Nonlinear bending analysis of FG-CNTRC plate resting on elastic foundation by natural element method

A nonlinear numerical analysis is addressed for a functionally graded carbon nanotube-reinforced composite (FG-CNTRC) plate on elastic foundation. The large deflection bending problem is formulated according to the von Kármán nonlinear theory and the (1,1,0)* hierarchical model. And, it is numerically solved by 2-D (two-dimensional) natural element method (NEM) which is characterized by a high accuracy even for coarse grid. The derived nonlinear matrix equations are iteratively calculated by combining the load increment scheme and the Newton-Raphson iteration method. The present method was verified through the benchmark test, where the present method shows excellent agreement with the reference solutions. The nonlinear behavior of FG-CNTRC plate on elastic foundation is evaluated in terms of the non-dimensional deflection and bending moment. These non-dimensional quantities are examined with respect to the foundation stiffness, the volume fraction and gradient pattern of CNT, the aspect and width-thickness ratios of plate and the boundary condition. From the parametric experiments, it is found that both non-dimensional quantities are significantly influenced by such parameters.

Preparing Biomass Carbon Fiber Derived from Waste Rabbit Hair as a Carrier of TiO2 for Photocatalytic Degradation of Methylene Blue.

In the past few years, biomass carbon materials have gained wide attention from many scholars as TiO2 carrier materials to improve photocatalytic activity due to their renewable, green, low-cost, and high-efficiency advantages. In this study, TiO2/carbonized waste rabbit fibers (TiO2/CRFs) nanocomposites with the hierarchical microporous/mesoporous structure were fabricated by a combination of carbonization, immersion, and calcination methods using tetrabutyl titanate as the titanium source and waste rabbit hair as the carbon source. The properties and catalytic activity of TiO2/CRFs composite were evaluated based on several characterization techniques and methylene blue (MB) photodegradation studies. The results showed that the degradation of MB by TiO2/CRFs could reach 98.1% after 80 min of solar irradiation. Moreover, TiO2/CRFs still maintained high photocatalytic activity after five cycles of degradation tests, exhibiting good stability and reusability. The improved photocatalytic performance of TiO2/CRFs materials is attributed to the natural carbon and nitrogen element doping of TiO2/CRFs and its morphology, which reduces the compounding of photogenerated electron-hole pairs and narrows the TiO2 band gap, while the multiple reflections of visible light in the pore channels enhance the visible light absorption of the materials. Furthermore, the large specific surface area provides abundant reaction sites for adsorbed reactants. This paper provides the experimental basis for the application of waste rabbit biomass carbon composites in photocatalytic degradation field.

Advances of biosensors for UO22+ detecting based on specific DNAzyme

• This review summarizes the different types of biosensors for the detection of UO 2 2+ on the basis of specific DNAzymes and established by different signals in recent years.This review provides significant references for the further development of biosensors. • This review provides valuable information for the application of sensors in human body. Uranium, as a natural radioactive element, can be a nuclear fuel and widely used in industry and medicine, which also can cause serious harm to the human body during its processing and enriching. The detection methods of UO 2 2+ in water have gotten the attentions of researchers and become a hot research topic. DNAzyme can be used as a probe for UO 2 2+ detection owing to its high specificity and sensitivity. This review summarizes the different types of biosensors for the detection of UO 2 2+ on the basis of specific DNAzymes and established by different signals in recent years, among which many attempts in changing the structure of DNAzyme have been made to improve the biosensors for detecting UO 2 2+ . With the continuous development of more simple, fast and sensitive sensor technology, the sensors based on specific DNAzyme in UO 2 2+ detecting have very broad research prospects in the future.

There's No Sport Without Spectators - Viewing Football Games Without Spectators During the COVID-19 Pandemic.

The presence of sports fans in the stands is considered a natural and essential element of sporting events. Beyond the atmosphere fans create and the color they add to the game, their presence reflects the idea that the game is more than a competition between two teams —it is a grand battle between communities and identities, which is also the reason that fans are willing to sacrifice so much on behalf of their team. As is other areas of life, the COVID-19 pandemic created an unusual situation, in which sporting events were held without spectators in the stadium stands. In many places around the world, professional sporting activities were permitted but spectators were not allowed into the stadiums due to social distancing restrictions. The current study examines this unique situation and through it, gains an understanding of fans’ beliefs concerning the significance of spectators and their presence in the stadium. Through in-depth interviews with football fans who regularly attend games (in the pre-pandemic period), the current study explores football fans’ experiences as they viewed “ghost games” (where teams played to empty stadiums). Findings show that this unique situation, caused by the global pandemic, heightened fans’ deep-rooted connection to sports and to their favorite team, and also exacerbated the social, emotional, and professional implications of viewing football games with no spectators.

Natural radioactivity and element characterization in pit lakes in Northern Sweden.

Northern Sweden has been the object of intense metal mining in the last decades producing several water-filled open-pits, or pit lakes. Most of these pit lakes have been limed to maintain a good water quality and to prevent generation of acidic water that could leach the exposed rocks and release metals into water. The aim of this work was to examine the concentration of stable elements and naturally occurring radionuclides in water and sediment samples from pit lakes originating from non-uranium mining activities in Northern Sweden. Surface water and surface sediments were collected from 27 pit lakes in Northern Sweden. Water quality parameters, concentration of stable elements and radionuclides were measured by a water probe, ICP-MS and XRF, and alpha and gamma spectrometry, respectively. Furthermore, a multivariate statistical analysis (PCA) was performed on the water samples and sediments. In general, the quality of the surface water was good, but some lakes had low pH values (2.5–5.7), and high concentrations of Fe (up to 200 mg/L) and other metals (e.g. Zn, Cu). When relating the metal concentrations in sediments in pit lakes with the concentration found in natural lakes, some sites had relatively high levels of Cu, As, Cr and Pb. The activity concentration of 210Po, and U and Th isotopes in water and sediment samples were at environmental levels, as was the ambient dose equivalent rate at these sites (range 0.08–0.14 μSv/h).

Buckling analysis of sandwich plates with FG-CNTRC layers by natural element hierarchical models

Buckling analysis of sandwich plates with FG-CNTRC layers by natural element hierarchical models

The Uneasy Coexistence of Expertise and Politics in the World Health Organization

Abstract The World Health Organization (who) has attracted an unprecedented level of criticism over its handling of the response to the covid-19 pandemic. To enhance its legitimacy and better prepare for a future pandemic, various proposals to reform the who and the International Health Regulations have been made. Against this background, this article seeks to contribute to the ongoing discussions by investigating the nature of who’s work and its activities. Starting from the premise that much of the criticism stems from the uneasy coexistence of politics and expertise in who’s work, this article analyses some of the most controversial aspects of who’s initial response to the covid-19 pandemic: (i) the alleged leniency towards China; (ii) the delay in declaring a public health emergency of international concern (pheic); and (iii) the delay in recommending the use of face masks for the general population. The article shows that politics infiltrates who activities in different ways, influencing even the processes that are conventionally seen as purely technical and science-based. At the same time, it argues that the influence of politics in who’s work should not be seen as some kind of atrophy, but should rather be considered a natural element that should be managed rather than dreaded.

Ontological Paradox of Computer-Based Technologies Used in Education and Learning.

This study sought to investigate the ontological paradox of computer-based technologies used in education and learning. The argument of this article is that today, the use of computer-based technologies to enhance learning and disseminate knowledge is indispensable; however, this leads to an onto-educational shift in the way we regard intellectual development of learners as a subjective factor in education and the employed learning technologies themselves; a natural human subjective element of learning and knowledge is considered to be ineffective, while technologically stored and transferred facts of knowledge are given higher regard. Computer-based technologies used in education are appraised and institutionalized to the height that learners are sometimes unable to reflect on their own without recourse to the aid of such technologies. It is not enough to employ technology and technologically enhance learning, but also we have to question its impact on the intellectual development of learners. Appropriating Heidegger’s phenomenology, the ontology of the human subject provides a philosophical and normative foundation for a comprehensive analysis of the use of computer-based learning in the technological frame since it allows us to rethink more seriously about subjective factors in education in today's growing technological society. This article recommends that the embracement of educational and learning technologies should consider both subjective and technological aspects; a blended education and learning system would be appropriate.

Ontological paradox of computer-based technologies used in education and learning

This study sought to investigate the ontological paradox of computer-based technologies used in education and learning. The argument of this article is that today, the use of computer-based technologies to enhance learning and disseminate knowledge is indispensable; however, this leads to an onto-educational shift in the way we regard intellectual development of learners as a subjective factor in education and the employed learning technologies themselves; a natural human subjective element of learning and knowledge is considered to be ineffective, while technologically stored and transferred facts of knowledge are given higher regard. Computer-based technologies used in education are appraised and institutionalized to the height that learners are sometimes unable to reflect on their own without recourse to the aid of such technologies. It is not enough to employ technology and technologically enhance learning, but also we have to question its impact on the intellectual development of learners. Appropriating Heidegger’s phenomenology, the ontology of the human subject provides a philosophical and normative foundation for a comprehensive analysis of the use of computer-based learning in the technological frame since it allows us to rethink more seriously about subjective factors in education in today's growing technological society. This article recommends that the embracement of educational and learning technologies should consider both subjective and technological aspects; a blended education and learning system would be appropriate.

Lost Symbols in the Historic City of Puebla in Mexico

Since its origin, the city of Puebla has had representative elements in its public spaces that have survived for a long time, they are ornamental and utilitarian objects which are landmarks of the city. Street furniture is a benchmark of identity too. All elements have legends, they are references that have given identity to streets and avenues. Natural elements also refer to a city’s identity, like trees. But the natural element that defined origin, trace and growth of the city is one of the least visible. In the sixties, the San Francisco River was piped, as a sign of the new modernity, and today it is a boulevard where thousands of cars pass. Thus, bridges and other types of elements that the population still remember, mainly the elderly, have been forgotten. In recent years, some initiatives have emerged to rescue the historical memory of daily life and the revaluation of repre­sentative objects of the city center, such as the Casa Analco Community Museum project, coordinated by the Faculty of Architecture of BUAP in collaboration with residents of the Analco neighborhood. This article discusses both the monuments, their relics, elements of nature that shape the city's identity, as well as the gradual loss of these symbols.

How to support young children's interest development during exploratory natural science activities in outdoor environments

This study examines how 4–8-year-old Norwegian children's interest in natural elements appears and develops during exploratory activities in various natural outdoor environments, and how teachers can support such interest in these settings. The results indicate that children's interest develops through three phases. Each phase can be recognised by how children relate to the natural element in question. They gain first-hand experience, are receptive to acquiring factual information and reflect on and apply their knowledge. Teachers can support children's interest by showing subject matter expertise and social and cognitive congruence. The significance of these different interactional characteristics varies between the phases.

URBAN WATERLINES: Socio‐natural Productions of Indifference in an Indian City

How is water engaged in, or mobilized for, the production of social difference and indifference? This article proposes the rubric of ‘urban waterlines’ to examine the political agency of various urban waters in inscribing categories of personhood and effects of discrimination. Waterlines are conceived as material (socio‐technical and historical) formations that set out to channel, contain or accelerate water, but are ultimately effected by pushbacks, overflows and outbreaks, or the subsidence and vanishing of water. They are dialectically assembled by the workings of water in two registers: first, as a variable form shaped by historically shifting valorizations of water as resource, factor of production, object of consumption, aesthetic feature, or waste; and second, as a relatively autonomous natural element that resists or exceeds these shapings. The article discusses three kinds of urban waterlines—boundaries, flows and infrastructures—using case studies from Chennai to illustrate how each is assembled through socio‐natural, technological and discursive operations and works to dispossess or disadvantage specific people and places. It brings Urban Political Ecology's analyses of water forms as historically crafted socio‐natural assemblages into conversation with anthropological scholarship on how indifference is produced through the everyday workings of the state.