Magnetic softening of young's modulus of amorphous Fe90Zr10
Abstract The Young's modulus and the internal friction of amorphous Fe90Zr10 alloy were measured near the Curie temperature using the vibrating reed technique. The modulus shows softening around Tc(= 227 K) and the internal friction undergoes drastic increase in the same temperature range. It is found that both the Young's modulus and the reciprocal of internal friction are inversely proportional to the magnetic susceptibility in the paramagnetic phase.
Magnetic and Mössbauer studies of amorphous (FeCo)90Zr10 alloys
Abstract Magnetization, susceptibility and Mossbauer measurements have been performed on a-Fe 90- x CO x Zr 10 ( x =0 to 90). Both the upper ferromagnetic (FM) transition at T c and the low temperature seemingly spin-glass-like anomaly have been observed. The time-dependent remanent magnetization (TRM, IRM) and hysteresis in the low temperature state have been studied.
Assessment of Ground Regeneration around Borehole Heat Exchangers between Heating Seasons in Cold Climates: A Case Study in Bialystok (NE, Poland)
Based on the experimental studies, the process of ground regeneration around the borehole loaded with brine-water heat pumps working exclusively for heating purposes in the period of four consecutive heating seasons in a cold climate was presented. The research was conducted in north-eastern Poland. The aim of the work is to verify the phenomenon of thermal ground regeneration in the period between heating seasons on the basis of the recorded data and to check whether the ground is able to regenerate itself and at what rate. It was noticed that the ground does not fully regenerate, especially during heating seasons with lower temperatures. In the analyzed period, from 22 September 2016 to 12 October 2020, the ground probably cooled irreversibly by 1.5 °C. In order to illustrate and evaluate the speed of changes in the ground, the one’s profile with an undisturbed temperature field was presented for each month of the year. The presented results can be a very important source of information for the analysis of geothermal conditions occurring in the ground. They can be used to verify mathematical models and conduct long-term simulations that allow us to see the complexity of the processes taking place in the ground.