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  • Author or Editor: A. Dąbrowski x
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Abstract  

The basic principle of comparing the sample mass with the mass of a reference body in equilibrium gives the equal-armed beam balance a unique accuracy. Main parameters characterising the suitability of the instrument are measuring range, resolution and relative sensitivity (resolution/maximum load). The historical development of the values of these parameters achieved depended strongly on the practical need in those times. Technically unfavourable scales of the oldest Egyptian dynasties (~3000 BC) could resolve mass differences of 1 g and had a relative sensitivity of at least 10–3. More sophisticated instruments from the 18th Dynasty (~1567–1320 BC) achieved a relative sensitivity of 10–4 independent of the size of the instrument. In 350 BC Aristotle clarified the theory of the lever and at about 250 BC Archimedes used the balance for density determinations of solids. The masterpiece of a hydrological balance was Al Chazini’s 'Balance of Wisdom’ built about 1120. Its relative sensitivity was 2⋅10–5. Real progress took place when scientists like Lavoisier (1743–1794) founded modern chemistry. At the end of the 19th century metrological balances reached a relative sensitivity of 10–9 with a maximum load of several kilogrammes. That seems to be the high end of sensitivity of the classical mechanical beam balance with knife edges. Improvements took place by electrodynamic compensation (Emich, Gast). In 1909 Ehrenhaft and Millikan could weigh particles of 10–15 g by means of electrostatic suspension. In 1957 Sauerbrey invented the oscillating quartz crystal balance. By observing the frequency shift of oscillating carbon nanotubes or of silica nanorods, masses or mass changes in the attogram or zeptogram have been observed recently.

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Abstract  

Specific surface area and pore size distribution are determined usually from adsorption isotherms at low temperatures using nitrogen or noble gases. These are not absolute parameters and the measuring methods are fraught with serious difficulties. General problems of sorption measurements and recent developments are discussed. To obtain information for practical purposes these measurements need to be supplemented by investigations of the sorbate/sorbent system used in practice. Results of the measurement of nitrogen and water vapour adsorption on different materials are compared.

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Abstract  

The thermal behaviour and phase composition of mixed oxides obtained by oxidation of iron(II) hydroxide in the presence of Mg, Zn, Co, Cu and Ni, is investigated by thermogravimetry, and conventional and high-temperature X-ray diffractometry.

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Abstract  

Results of calorimetric determination of integral enthalpies of solution of some hydrates (monohydrates and heptahydrates) of 3d transition metal sulphates such as FeSO4, NiSO4 and MnSO4 in three-component systems at sulphuric acid concentrations up to 2M are reported. Measured values of integral enthalpies of solution are the basis for calculation of activity coefficient temperature dependences according to Pitzer's model.

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Abstract  

Short survey on the latest developments on standardisation and standard reference materials for particles, surfaces and pore size analysis.

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Journal of Thermal Analysis and Calorimetry
Authors: A. Dąbrowski, E. Mendyk, E. Robens, K. Skrzypiec, J. Goworek, Mariola Iwan, and Zofia Rzączyńska

Abstract  

We investigated lunar regolith collected during the Apollo 11, 12 and the Apollo 16 missions. The Apollo 11 and the Apollo 12 samples come from the lunar mare, whereas the Apollo 16 expedition brought back material from a highland region of the near side of the Moon. In paper series we summarise in brief the results of measurements using photoelectron spectroscopy (XPS), Raman spectroscopy, X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), nitrogen adsorption, thermal analysis (TG, DTA) and temperature-programmed reduction and oxidation (TPRO) method. Parts of samples were examined by means of scanning electron (SEM/EDS) and atomic force microscopy (AFM).

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