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  • Author: Magdalena Dróżdż x
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GNSS Receiver Zero Baseline Test Using GPS Signal Generator

Validation of the performance of GPS receivers is crucial for many applications. This paper presents testing GPS receivers with the use of a GPS signal simulator. Unlike live testing, testing with simulators provides full control of simulated satellite signals and simulation environmental conditions. Moreover, generating repeatable signals makes possible to extend typical procedures. It allows to determine the absolute value of the position precision for each receiver without relation to any other one.

Abstract

The objective of the paper was assessment of the selected qualities of carrot from retailer's shops, organic and traditional food shops in Krakow. The following quality parameters of the fruit pulp were investigated: content of extract, sugars, polyphenols, nitrite, flavonoids, beta-carotene, colour, and antioxidant activity. The investigation shows that the content of nitrogen (V) in the samples of carrot from traditional cultivations was higher than in case of carrot from organic crops, and in case of a sample from traditional cultivation it exceeds the admissible norms. However, the research which was carried out provides no justification for the statement that the content of nitrate (III) depends on the production system of carrot. The research on the content of polyphenols, flavonoids and antioxidant activity of juice proved the increased antioxidant ability of carrot that was traditionally cultivated with reference to carrot cultivated organically. However, the differences were not statistically confirmed. Beta-carotene content in all samples was comparable regardless the cultivation system. Content of extracts, total carbohydrates and sucrose was significantly higher for carrot from traditional crops than for eco-carrot.

Abstract

In this paper, the impact of partial substitution of calcium for barium in (Ba1-xCax) (M0.9Y0.1) O3, M = Ce, Zr on physicochemical properties of the powders and sintered samples was investigated. The powders, with various contents of calcium (x = 0, 0.02, 0.05, 0.1), were prepared by means of thermal decomposition of organometallic precursors containing EDTA. All of the BaCeO3-based powders synthesised at 1100 °C were monophasic with a rhombohedral structure, however, completely cubic BaZrO3-based solid solutions were obtained at 1200 °C. A study of the sinterability of BaZr0.9Y0.1O3 and BaCe0.9Y0.1O3-based pellets was performed under non-isothermal conditions within a temperature range of 25 to 1200 °C. The partial substitution of barium for calcium in the (Ba1-xCax) (M0.9Y0.1) O3, M = Ce, Zr solid solution improved the sinterability of the samples in comparison to the initial BaCe0.9Y0.1O3 or BaZr0.9Y0.1O3. The relative density of calcium-modified BaCe0.9Y0.1O3-based samples reached approximately 95 to 97 % after sintering at 1500 °C for 2 h in air. The same level of relative density was achieved after sintering calcium-modified BaZr0.9Y0.1O3 at 1600 °C for 2 h. Analysis of the electrical conductivity from both series of investigated materials showed that the highest ionic conductivity, in air and wet 5 % H2 in Ar, was attained for the compositions of x = 0.02 to 0.05 (Ba1-xCax)(M0.9Y0.1)O3, M = Zr, Ce. The oxygen reduction reaction on the interface Pt│BaM0.9Y0.1O3, M = Ce, Zr was investigated using Pt microelectrodes. Selected samples of (Ba1-xCax) (M0.9Y0.1)O3, M = Zr, Ce were tested as ceramic electrolytes in hydrogen-oxygen solid oxide fuel cells operating at temperatures of 700 to 850 °C.