Technical Transactions iss. 18. Chemistry iss. 1-Ch

Technical Transactions iss. 18. Chemistry iss. 1-Ch

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Collection items (14)


Diffused phase transition in polycrystalline (Ba0.70Pb0.30)(Ti0.70Sn0.30)O3

Ziętek, Dorota
Article
2014
In this paper, the method of manufacturing solid solution (Ba0.70Pb0.30)(Ti0.70Sn0.30)O3 (BP30TS30) is presented. Dielectric spectroscopy and scanning electron microscopy methods were applied to investigate the influence of doping by Pb and Sn on the physical properties of BaTiO3 (BT). It is shown that Pb and Sn substitutions change the temperature of phase transitions, their character and the maximum value of electric permittivity.

An analysis of the elemental composition of micro-samples using EDS technique

Wassilkowska, Anna, Czaplicka-Kotas, Anna, Zielina, Michał, Bielski, Andrzej
Article
2014
A classic example of the application of electron-dispersive spectroscopy (EDS) is the observation of the microstructure of solid samples using scanning electron microscope (SEM). This provides the possibility of taking measurements of chemical composition in very small areas. Measurements can be performed on any bulk sample through adjusting the X-ray excitation parameters to the elements of its expected composition. Examples of the applications of the EDS technique in the context of environmental engineering have been presented.

Advantages of the application of fluidized bed bioreactors to a microbiological nitrification process

Tabiś, Bolesław S., Stryjewski, Wojciech S.
Article
2014
The paper presents application possibilities of two and three-phase fluidized bed bioreactors for carrying out a microbiological nitrification process. The advantages and disadvantages of individual bioreactors are described. A quantitative analysis of the fundamental operating variables related to the balance of oxygen and the preservation of the fluidized bed was performed.

Influence of vanadium dopping on dielectric properties of barium titanate ceramics

Stanuch, Krzysztof
Article
2014
The purpose of this article is to present the impact of vanadium substitution on the dielectric properties of barium titanate. Doping barium titanate (BaTiO3) by different ions such as vanadium V5+ provides the possibility of changing its dielectric properties. SEM images indicate the differences between pure BaTiO3 (BT) and Ba(Ti0.98V0.02)O3 (BTV2). Using dielectric measurements, the Curie temperatures (Tc) were calculated – they were found to be equal to 403 K and 396 K, respectively. Moreover, for BTV2 the Curie - Weiss temperature and the Curie constant (C) were determined (T0 = 368 K and C = 1.46 ×105 K, respectively).

Prospects of using mechanochemical syntheses in the fabrication of composite powders for tribotechnology

Sikora, Teodora, Wieczorek-Ciurowa, Krystyna
Article
2014
The aim of tribotechnological research is the reduction of tribo-couple wear through the optimization of the functional properties of the materials. Polymer matrix composites enriched by powdered materials (e.g. metal-ceramic composite powders) have a wide range of applications in the field of tribotechnology. The possibilities of producing such fillers via green, environmentally-friendly syntheses using the high-energy ball milling process are presented.

Simplified methods for the determination of hydrogen sulphide acid in sediment contaminated by mining activities

Parvinen, Pekka, Wieczorek-Ciurowa, Krystyna
Article
2014
The concentration level of hydrogen sulphide acid in the sediment contaminated by mining activities can be applied as criteria ability of sediments to bind the heavy metals and mobility of such metals. The determination of hydrogen sulphide acid (HSA) by molecular absorption spectrometry and combustion-IR analysis in sediment samples is described. The liberation of H2S is performed through the addition of the concentrated sulphuric or hydrochloric acid. The liberated hydrogen sulphide is measured directly using molecular absorption spectrometry (MAS) and by absorbing the HSA in a silver nitrate solution and measuring the precipitated sulphur by combustion (the IR method). The lowest determinable concentrations were at the level of 2–10 mg g–1.

Physicochemical and microbiological characteristics of pig slurry

Marszałek, Marta, Kowalski, Zygmunt, Makara, Agnieszka
Article
2014
Pig slurry is classified as a natural fertilizer of animal origin, being a mixture of faeces, urine, remains of fodder and water used for the elimination of faeces. It is generated in non-bedding pig farming conditions, where animals are kept on slatted floors (grate or slotted floor). This paper presents the general characteristics of pig slurry, its physicochemical properties and its microbiological composition. Also, factors affecting slurry properties are discussed.

Temperature profiles in ground heat exchangers

Larwa, Barbara, Kupiec, Krzysztof
Article
2014
A mathematical model of a ground heat exchanger cooperating with a heat pump was presented. The model is based on a one-dimensional heat conduction equation with an internal heat source. On the basis of the solutions to the model equations, both the temperature distribution of different types of ground at different times of year as well as the time courses of temperature at different depths are shown. Calculations based on the presented model can be useful for the simulation and design of this apparatus.

The use of hyaluronic acid in the treatment of osteoarthritis of knee cartilage

Kwasek, Beata, Bogdał, Dariusz
Article
2014
The aim of this paper is to describe the possibilities of the therapeutic use of hyaluronic acid (HA) in the treatment of osteoarthritis of knee cartilage. This work provides an overview of the literature relating to the structure of hyaluronic acid, its properties and important functions of the human body. Moreover, the construction of the articular cartilage in the knee joint, including events leading to its degeneration, is presented. Viscosupplementation is a treatment for osteoarthritis involving several intra-articular injections of HA at specific time intervals. This treatment results in an increased lubricity, viscosity and elasticity of articular cartilage. Since HA is found naturally in the human body, viscosupplementation improves the biomechanical conditions of the joint whilst minimizing the side-effects of treatment. Hyaluronic acid occurs naturally in a linear form, but for many applications, chemical modifications are necessary. Thanks to this property, it remains in the body long enough to produce the desired therapeutic effect. Modification processes, in particular the cross-linking of HA, increase the mechanical properties of knee cartilage. HA is an example of a new kind of tissue engineering scaffold that is bioactive in both full-length and degraded forms. In turn, hydrogel scaffolds with interpenetrating polymeric network (IPN) gels can simulate the structure of the native extracellular matrix of cartilage tissue.

Methods for the determination of hexabromocyclododecane in food

Kuc, Joanna, Grochowalski, Adam
Article
2014
Methods of sample preparation with a particular emphasis on extraction and purification techniques are described. Gas and liquid chromatography techniques applied for the determination of hexabromocyclododecane are presented. Issues relating to the determination of this compound in food samples are discussed.