Sklářský výrobní okruh z 2. poloviny 13. století u Jilmové v Krušných horách Přínos analytických metod pro poznání technologie výroby středověkého skla v Čechách / The glass production area near Jilmová in the Ore Mountains from the second half of the 13th century The contribution of analytical methods for studying glass production technology in medieval Bohemia

The study contains the latest knowledge concerning glass production at the beginning of the High Middle Ages in one of the oldest glass production areas in the Ore Mountains consisting of three glassworks located in the upper reaches of the mountains. The work presents archaeological sources obtained in excavations at the Jilmová I, II and III sites, with attention being focused on finds specific to glass production centres, i.e., mainly fragments of technical ceramics – melting pots, crucibles and the waste accompanying various stages of glass production. The classic typological­morphological analysis is accompanied by a detailed archaeometric analysis. The results of spectrometric analyses (XRF, XRD, SEM–EDS and LA–ICP–MS) expand the informative value of archaeological finds and help refine existing knowledge of glass production technology in the second half of the 13th century.

APPLICATION OF ART GLASS IN INTERIORS OF PUBLIC BUILDINGS

The aim of the research is to identify the compositional methods of using art glass in the interiors of public buildings in order to increase their aesthetic expressiveness. In the article the information on the history of art glass development is given. According to the results of the historical analysis, it is concluded that new directions of glass application arose with the development of new technologies of glass production and processing - this process continues to this day. An overview of the state of study of the problem, in particular the research of Kazakova L.V., F.Petryakova, Som-Serdyukova O.M., Daineko V.V., and identified the main areas in which research is conducted. The physical properties of glass and its types by technological features are considered. A historical overview of the development of gutnitsy on the territory of Ukraine. The two main trends in studio glassmaking to date have been identified and a conclusion has been drawn about the evolution of art glass from the subject form to the art object. The current state of art glass formation is characterized by associativity, metaphoricalness, and increased decorativeness. The classification of art glass according to the function of application in public interior is carried out. The basic compositional methods of placing art glass in the space of public interior are revealed. Three degrees of integration of art glass with elements of architecture are formulated: the decor on architectural elements, as a part of architectural elements, is directly an architectural and constructive element. Examples of objects that demonstrate the integration of art glass with architectural elements are given. Henri Matisse's stained glass windows in the Dominican Sisters' Chapel in Mans, France, are described as an example of the use of the "rhythm" compositional technique and Dale Chihuly's glass garden gallery in Seattle with a glass installation that dominates the pavilion. It is concluded that the choice of compositional methods of including art glass in the interior space depends on many factors - the functional purpose of the room, the specifics of space, its size, etc. and should take into account aspects of its psychological impact on man, principles of structural and compositional organization and features life processes.

Glass Production from River Silica of Bangladesh: Converting Waste to Economically Potential Natural Resource

The Ganges-Brahmaputra river system at the Bengal Basin carries large amounts of sediments on the way to finally deposit at the Bay of Bengal. Those river-transported sediments form bar deposits during dry season in many areas of Bangladesh and accumulate economic mineral depositions at suitable geological environments. Dredging is a must for most of those rivers for proper navigation, as well as protecting bank erosion, which generates millions of tons of waste sand. The dredged materials from river beds are mostly composed of silicate minerals, especially quartz and feldspar along with several dark colored heavy minerals. Like the industrial processing of heavy minerals from bulk sands, various physical separation techniques can be utilized for the beneficiation of silica from those river-born silicate minerals in dredged sands. Those silica have been successfully upgraded to near-glass sand grade in the laboratory, however, they have yet to be utilized for any kind of commercial venture. The present study attempts characterization of several river sands through physical separation and laboratory analysis. The upgraded silica was successfully compared with several quality glass sands and laboratory production of glasses. This experimental production of glass from upgraded silica could potentially be economical considering its industrial application with positive environmental consequences through minimizing the dredging cost, increasing the navigability of the river and ecological balance along the flood plain.

Extraction of Potassium from Feldspar by Roasting with CaCl2 Obtained from the Acidic Leaching of Wollastonite-Calcite Ore

Potassium, which is included in certain contents in the structure of K-feldspar minerals, has a very important function in the growth of plants. Turkey hosts the largest feldspar reserves in the world and is by far the leader in feldspar mining. The production of potassium salts from local natural sources can provide great contributions both socially and economically in the agriculture industry along with glass production, cleaning materials, paint, bleaching powders, and general laboratory purposes. In this study, potassium extraction from K-feldspar ore with an 8.42% K2O content was studied using chloridizing (CaCl2) roasting followed by water leaching. Initially, to produce wollastonite and calcite concentrates, froth flotation tests were conducted on wollastonite-calcite ore after comminution. Thus, wollastonite and calcite concentrates with purities of 99.4% and 91.96% were successfully produced. Then, a calcite concentrate was combined with hydrochloric acid (HCl) under optimal conditions of a 1 mol/L HCl acid concentration, a 60 °C leaching temperature, and a 10 min leaching time to produce CaCl2. To bring out the importance of roasting before the dissolution process, different parameters such as roasting temperature, duration, and feldspar—CaCl2 ratios were tested. Under optimal conditions (a 900 °C roasting temperature, a 60 min duration, and a 1:1.5 feldspar—CaCl2 ratio), 98.6% of the potassium was successfully extracted by the water leaching process described in this article.

Life-cycle assessment of a photovoltaic panel: Assessment of energy intensity of production and environmental impacts

A number of articles have already been published on energy recovery from the sun using solar panels and their environmental impacts. However, in this article, we assess the impact of solar panel technology, and use separately obtained data based on the disassembly of a specific photovoltaic panel into discrete parts. The aim of this article is to list all the environmental impacts of this panel per unit of energy produced and at the same time to focus primarily on deciphering the energy intensity of individual phases of the life cycle of photovoltaic panel production. An analytical method of Life-cycle assessment using the environmental software version SimaPro 9.0.049 with an integrated Ecoinvent 3 database was used to determine the environmental impacts. Throughout the work, we focus on the data obtained, which shows that the process of photovoltaic panel production itself is very energy-intensive, especially in the phase of photovoltaic cell production and solar glass production. In other phases, which is the production of individual parts of the photovoltaic panel, its use, and subsequent recycling, they do not contribute so much to the overall energy balance. In the environmental impact assessment, the most affected aspects were human health, followed by climatic change, resources, and the ecosystem quality came last. In all four of the above categories, the influence of the photovoltaic cell production phase was determined to be dominant.

Homotopy perturbation method solution of magneto-polymer nanofluid containing gyrotactic microorganisms over the permeable sheet with Cattaneo–Christov heat and mass flux model

Many non-Newtonian materials behave as a polymeric solution and this type of materials is used in various industrial and physical applications such as polymer extraction, manufacturing processes, various geophysical systems, and glass production. Especially the gyrotactic microorganisms have widely used for the production of biodiesel, hydrogen, an essential sustainable energy source and in water treatment plants. This study intends to examine the impacts of magnetic field, convective boundary state on bioconvection of a tangent hyperbolic nanofluid in the presence of gyrotactic microorganisms over a porous stretching surface with a Cattaneo–Christov heat and mass flux model. Appropriate self-similarity variables are implemented to transform the fluid transport equations into ordinary differential equations that have been resolved using the homotopy perturbation method. The influences of effective parameters on transport properties of the fluid are represented with graphs and tables. This model forecast the shear-thinning attitude significantly and exactly describes the flow of fluids. It is noted from the obtained results that the velocity profile declines with raising the Weissenberg number and buoyancy ratio parameter. It also observed that the temperature profile rises with a growth in the radiation and thermal relaxation parameters. The higher values of the stagnation parameter increase the rate of heat transfer while it is opposite nature in the mixed convection parameter. Microorganisms density uplifts with an increase in Peclet number, while it decreases for the microorganism concentration difference. Microorganisms density increases with an enlargement in bioconvection Schmidt number.

WCZESNOŚREDNIOWIECZNY SZKLANY PACIOR Z KRUSZWICY

In the gord in Kruszwica, on the settlement level from the 4th quarter of the 11th century, a piece of a large bead was discovered. It was made of black and purple glass, decorated with a set glass thread and small buttons with the (floral) millefiori ornament. It was made of glass, the “ash” variety of the Na2O-K2O-CaO-MgO-Al2O3-SiO2 type (the grains) and the Na2O-K2O-CaO-MgO-Al2O3-PbO-SiO2 type (the ornament). An interpretation of the results of an analysis of the chemical content of the glass (XRF, X-Ray Fluorescence) has allowed to define the probable place of the glass production, as well as the form and type of this rare specimen, namely the Middle East (probably Byzantine) workshops.