Browsing by Subject "solution"

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Access status: Open Access ,
A study of the properties of forming mixtures containing polystyrene wastes
(AGH University of Science and Technology Press, 2021) Dan, Olena; Trofimova, Larisa Alekseevna
Expanded polystyrene is widely used as a material for packaging, in modern construction as a heat and sound insulation layer, in thermal insulation systems for buildings, as well as tanks and pipelines. It is additionally used in foundry engineering for the production of models which are gasified during the production of castings from ferrous and non-ferrous alloys under the contact with liquid metal. The use of expanded polystyrene products is associated with waste generation, both in production and in consumption. About 40-50 kg/person of polystyrene waste is generated per year. The peculiarity of polymeric wastes is their resistance to aggressive environments. They do not rot and the destruction processes in natural conditions proceed rather slowly, with the formation of harmful substances that poison the environment. Therefore, the problem of the processing of waste from polymeric materials is of great importance, not only from the standpoint of environmental protection, but also due to the fact that in conditions of a shortage of polymer raw materials, this waste becomes a powerful raw material resource. This article describes the prospects for recycling expanded polystyrene wastes in foundry engineering. In this work, the properties of molding and core sands containing a combined binder, consisting of a solution of expanded polystyrene wastes in turpentine and clay were investigated, and their main characteristics (weight during stretching and crumbling) were determined. Molding and core mixtures, which contain only a binder in the form of a solution of expanded polystyrene in turpentine, have a crude strength of not more than 0.01 MPa. The introduction of a mixture of clay in the amount of 2-3% allows a crude strength of the mixture of up to 0.05 MPa to be obtained. After drying, the investigated mixtures containing a solution of expanded polystyrene wastes and clay have a tensile strength of up to 2.1 MPa. Mixtures into which a solution of polystyrene wastes and clay was introduced have an insignificant gas capacity and satisfactory gas permeability.
Access status: Restricted ,
Badania modelowe i transformacje składu chemicznego roztworów porowych w strefie aeracji składowisk odpadów górniczych
(Data obrony: 2010-02-16) Cichoń, Dorota
Wydział Geologii, Geofizyki i Ochrony Środowiska
The purpose of this document is to present the changes in leek solution chemical compositionin mining waste landfill aeration zones. The period of the research was from 22.07.2005 until 07.07.2006 on a model object on the AGH grounds, it consisted of the collection of lysimeter samples SM1, SM2 and atmospheric precipitations, regularly collected every two weeks. This is a continuation of a research from 1985 led by the department of hydrogeology and geology engineering about mining hard coal waste.
Access status: Open Access ,
Fractional order Riemann-Liouville integral inclusions with two independent variables and multiple delay
(2013) Abbas, Saïd; Benchohra, Mouffak
In the present paper we investigate the existence of solutions for a system of integral inclusions of fractional order with multiple delay. Our results are obtained upon suitable fixed point theorems, namely the Bohnenblust-Karlin fixed point theorem for the convex case and the Covitz-Nadler for the nonconvex case.
Access status: Open Access ,
Rozwiązanie równania czwartego stopnia w przypadku dwóch par pierwiastków zespolonych sprzężonych
(Wydawnictwa AGH, 2009) Górecki, Henryk
Istnieje wiele metod [4] rozwiązywania równania czwartego stopnia. Między innymi można tu wymienić następujące: metoda Ferrari, metoda Descarta, metoda Eulera. Jednakże wszystkie te metody prowadzą do skomplikowanych wzorów. W artykule niniejszym podano nową metodę, która w przypadku dwóch par pierwiastków zespolonych sprzężonych, prowadzi do prostych wzorów.