This paper presents the results of investigations into the structure, microstructure and magnetic properties of Fe
Co
amorphous alloy. The alloy samples were in two physical forms: (1) plates of ...approximate thickness 0.5 mm (so-called bulk amorphous alloys) and (2) a ribbon of approximate thickness 35 μm (so-called classic amorphous alloy). The investigations comprised: X-ray diffractometry, Mössbauer spectrometry, transmission electron microscopy, and selected magnetic measurements; all of the investigations were carried out on samples in the as-quenched state. Analysis of the obtained SEM and TEM images, X-ray diffraction patterns, Mössbauer spectrometry results and measurements of the magnetisation in a high magnetic field facilitated collectively the detailed description of the structure of the investigated alloy, which was found to depend on the quenching speed.
The research presented in detail in this scientific paper refers to the modelling of process parameters for natural gas transmission in a centralized system. The method of the factorial experiment ...was used to model some parameters considered to be vital, namely the gas temperature, the air temperature as well as a certain correction factor on the flow delivered to the population. The study was conducted by accessing information provided by a regulation-measurement station that delivers gas to an important locality in a locality in central Romania. Experimental data collected over 24 hours on a summer day but also on a winter day were used. After a previous study with classical experimental research methods, the factorial experiment was used, which allows the delivery of much more detailed information and the graphical representations are much more precise and detailed, in other words, relevant and useful conclusions can be obtained on objective studied in the research approached.
•Influence of rapid quenching method on structure and magnetic properties.•Bulk and classical amorphous alloy in the as-cast state.•Samples were obtained by the use of three different techniques.•XRD ...and Mössbauer effect studies were used to confirm amorphous structure of samples.•Local environment of the Fe atoms contribute to the change of magnetic properties.
Mössbauer spectroscopy enables the determination of the influences of quenching rate and production method on the microstructure and magnetic properties of resulting ferromagnetic amorphous materials. On the basis of analysis of the hyperfine field distributions obtained from Mössbauer spectra, it has been ascertained that, in the volume of three samples manufactured by different production methods, differences exist in the local environments of the Fe atoms; further, that these differences contribute to observed variations in the magnetic properties. Analysis of the high-field magnetization curves has facilitated the calculation of the spin wave stiffness parameter. From this parameter, the range and strength of the exchange interactions could be determined.
Zeolite has been successfully synthesized from clay and rice husk ash in the form of powder by using the hydrothermal method with variations in chemical compositions of alkaline solution and the ...amount of rice husk ash. The clay raw material was obtained from the Sidrap area of South Sulawesi and rice husk ash is obtained from the burning pile of rice husks. Sidrap clay and rice husk ash were activated using an alkaline solution of NaOH and varied rice husk ash and the addition of AlCl3. The addition of AlCl3, an alkaline solution of NaOH and H2O was used in the amount of 25.5 grams and variations of rice husk ash were 2.5 grams and 6.5 grams. Meanwhile, without the addition of AlCl3, an alkaline solution of NaOH and H2O was used for 20.5 grams and variations of rice husk ash from 2.5 grams and 6.5 grams. Then the mixture was then put into an autoclave with a temperature of 100°C for 3 hours. The basic material used in the manufacture of zeolite is carried out by X-ray Fluorescence (XRF) characterization to determine the constituent elements of basic material, which showed the content of SiO2 was 45.80 wt% in the clay and 93.40% in the rice husk ash. The crystalline structure of the zeolite formed was characterized by X-Ray Diffraction (XRD). It was found the resulting zeolite were identified as Zeolite-Y, Hydrosodalite, and ZSM-5. The microstructure properties of the resulting zeolite were determined by using Scanning Electron Microscopy (SEM).
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