Browsing by Subject "thermal analysis"

Now showing 1 - 9 of 9

Access status: Open Access ,
Alunogen from the sulfate efflorescence of the Stone Town Nature Reserve in Ciężkowice (the Outer Carpathian Mountains, Poland)
(Wydawnictwa AGH, 2023) Marszałek, Mariola; Gaweł, Adam
Alunogen $(Al_{2}(SO_{4})_{3} \cdot 17H_{2}O)$, a rare secondary mineral, has been found in the efflorescence on sandstones from the Stone Town Nature Reserve in Ciężkowice, southeastern Poland. This is probably the first find of this salt on such rocks in Poland. Alunogen forms in various geological environments, but mainly from the oxidation of pyrite and other metal sulfides in ore deposits and Al-rich Earth materials under low-pH conditions. Its crystallization at this particular site depends on a set of necessary physicochemical (pH, concentration), climatic (season, temperature, humidity), site-related (location and protection of efflorescence), and mineralogical (the presence of pyrite) conditions. This paper presents the mineralogical and geochemical characteristics of the alunogen from the Stone Town Nature Reserve (based on SEM-EDS, XRPD, EPMA and Raman spectroscopy methods) as well as of the efflorescence itself (based on XRPD and STA coupled with QMS and FTIR for the analysis of gas products). Crystals of alunogen take the shape of flakes, often with a hexagonal outline, clustered in aggregates forming a cellular network. Its calculated formula is $(Al_{1.96}Fe^{3+}_{0.01})_{\Sigma1.97}(SO_{4})_{3} \cdot 17H_{2}O$ (based on 12 $O$ and 17 $H_{2}O$). The unit-cell parameters refined for the triclinic space group P1 are: $\alpha$ = 7.423 (1) Ǻ, $b$ = 26.913 (5) Ǻ, $c$ = 6.056 (1) Ǻ, $\alpha$ = 89.974 (23)°, $\beta$ = 97.560 (25)°, $\gamma$ = 91.910 (22)°. The Raman spectra ($SO_{4}$) bands are: intensive 995 cm$^{-1}$ ($ν_{1}$), low-intensive 1069, 1093 and 1127 cm$^{-1}$ ($ν_{3}$), low-intensive 419 and 443, medium-intensive 470 cm$^{-1}$ ($ν_{2}$), and medium-intensive 616 cm$^{-1}$ ($ν_{4}$). Those at 530, 312 and at 338 cm$^{-1}$ are assigned to water vibrations and those at 135, 156, 180 cm$^{-1}$ to the lattice modes. Although the efflorescence contained an admixture of other minerals (pickeringite, gypsum and quartz), the predominant alunogen is almost chemically pure and the above parameters are consistent with the values reported in the literature for alunogen from different locations and of various origins.
Access status: Open Access ,
Analysis of cooling curves of nodular cast iron
(AGH University of Science and Technology Press, 2018) Bartošová, Marianna; Pribulová, Alena; Futáš, Peter; Eperješi, Štefan
The solidification of cast iron is a complex process with characterized entrance and marginal conditions. Thermal analysis is one of the processes that allows us to observe the solidification of alloys. There is a possibility of gaining information about the melted cast iron quality and predicting the final properties of the cast by evaluating the scanned cooling curves by solidification (stable and metastable system). This article deals with the study and analysis of cooling curves taken from production conditions of a foundry during ductile cast iron production. The aim is to discover the reproduction and reliability of the thermal analysis results of cast iron. The study of the progress of the cooling curves and their first derivation to follow the reactions of the curves to changing factors in the production process.
Access status: Open Access ,
Identification of the heat source and thermal material model parameters for the laser engineered net shaping
(Wydawnictwa AGH, 2022) Hajder, Lucyna; Zhang, Tao; Nguyen, Vu
The research's primary goal is to identify the heat source and thermal material model parameters for the numerical simulation of the laser engineered net shaping (LENS). Inconel 718 was selected as a case study for the current investigation. The LENS process's numerical model was developed within commercial finite element software and was used as a direct problem model during the parameter identification stage. Experimental data were obtained based on a rectangular-shaped sample with thermocouples located under the based material surface. The recorded thermal profiles were used to establish a goal function for the parameter identification stage. As a result, parameters describing the melt pool geometry during the additive manufacturing, as well as thermal coefficients describing interactions between the sample material and surrounding/base material, were determined.
Access status: Open Access ,
Novel measurement method to study thermal aspects of molding mixture decomposition
(AGH University of Science and Technology Press, 2018) Svidró, József Tamás; Diószegi, Attila
A wide variety of molding mixtures are extensively used in the process of the sand casting of metal components today. The sector is continuously developing in production volume, moreover, the expectations of customers are increasing on a monthly basis (also from a quality point of view). Even though mold and core manufacturing are well-organized routines in most foundries, technological problems still appear that can lead to technological problems and casting defects. These trends are forcing metal casters to come up with fitting strategies to solve their daily production challenges, while their suppliers are expected to keep up the continuous development of their existing foundry products and to find innovative solutions as well as new material combinations. Research on molding materials and their properties must, therefore, take a step forward accordingly to generate the necessary new knowledge to understand the behavior of mold and core mixtures during casting. This paper summarizes the latest results of a novel measurement method suitable for studying the degradation characteristics of different molding materials from a new perspective. The fundamentals of the method are based on a thermal analysis, focusing on the heat-absorption behavior of greensand and two types of chemically bonded sands regardless of the binder type and amount or the manufacturing process.
Access status: Open Access ,
Określanie właściwości popiołów lotnych przy użyciu różnych metod i urządzeń badawczych
(Wydawnictwa AGH, 2009) Szponder-Kołakowska, Dominika Katarzyna; Trybalski, Kazimierz
Fly ash is noxious waste that comes from minerals substances dispersed in coal and are subjected to many physical and chemical processes during coal combustion. Because of different types of coals, different types of combustion, a high level of dispersion of mineral substances in coals and the duration of thermal processes, the particles of fly ash are diversified as to their structure, phase and chemical composition. The diversity of produced fly ash makes it necessary to determinate their physical, chemical and mineralogical properties in order to select suitable utilization method. This paper presents a few research methods and measuring devices used to determine physical, chemical and mineralogical properties of raw and waste materials and also their usefulness to characterize fly ashes properties.
Access status: Restricted ,
Próba oznaczenia składu fluidów mineralizujących w agatach z Asni (Maroko), metodą analizy termicznej z Kwadrupolowym Spektrometrem Masowym (STA)
(Data obrony: 2019-02-01) Kałużyńska, Katarzyna
Wydział Geologii, Geofizyki i Ochrony Środowiska
Celem niniejszej pracy była próba przedstawienia i scharakteryzowania związków ciekłych oraz gazowych zamkniętych w inkluzjach w agatach pochodzących z miejscowości Asni w Maroko. Sprawdzano obecność takich związków jak H2O, HF, NO, S, SO i CO3 dla których nie było interferencji z innymi fazami o tej samej masie atomowej. Praca miała charakter eksperymentalny, polegający na próbie powtórzenia badania oznaczania składu fluidów w na podstawie pracy Richter-Feig et al. (2018). Analizie termicznej w zakresie temperaturowym 0-1400 oC poddano cztery próby, które były podobne pod względem wielkości i barwy. W wyniku analizy uzyskano krzywe TG, DTA, DTG, QMS dla 3 agatów. Na podstawie badań stwierdzono jedynie obecność takich związków jak H2O, CO2 oraz S.
Access status: Open Access ,
TG-DTG-DSC, FTIR, DRIFT, and Py-GC-MS studies of thermal decomposition for poly(sodium acrylate)/dextrin (PAANa/D) – new binder BioCo3
(2017) Grabowska, Beata; Kaczmarska, Karolina; Bobrowski, Artur; Żymankowska-Kumon, Sylwia; Kurleto-Kozioł, Żaneta
TG-DTG-DSC, FTIR, DRIFT, and Py-GC-MS studies have been conducted to determine the effect of the thermal decomposition conditions and structure of foundry binder BioCo3 in the form of a composition poly(sodium acrylate)/dextrin (PAANa/D) on the progress of degradation in terms of processes occurring in foundry sands in contact with liquid metal. TG-DTG-DSC curves of the composition allowed us to determine the temperature range in which they do not undergo degradation, by which they do not lose their binding properties. With temperature increasing, physical and chemical changes occur that are related to the evaporation of solvent water (20–110°C), followed by the release of constitution water, and finally intermolecular dehydration (110–230°C). In this temperature range, processes that are mainly reversible take place. Within a temperature range of 450–826°C, polymer chains are decomposed, including the decomposition of side chains. Within a temperature range of 399–663°C, polymer composition decomposition can be observed (FTIR, DRIFT), and gas products are generated from this destruction (Py-GC-MS).
Access status: Open Access ,
The optimization of a numerical steel foundry simulation through a characterization of the thermal properties of the materials
(AGH University Press, 2022) Souêtre, Morgan; Vaucheret, Alexis; Jacquet, Philippe; Carton, Jean-François
In many foundries, numerical simulation is used to determine the origins of different defects as this tool allows the acceleration of the design process. However, the databases provided by different software do not seem to tally with the actual properties of the material. In fact, every foundry uses a different grade of steel and varying mixtures of sand. An evaluation of the impact of different material properties showed the importance of measuring every physical property to improve the database of the software. Following this, an experiment was conducted to evaluate the gap between numerical simulations and the results obtained through experimentation. This experiment, called thermal analysis, consists in measuring the solidification and cooling of a cylinder filled with liquid steel. After the calculation of the steel properties and a simulation with real experimental parameters, a comparison between each cooling curve was realized. This comparison shows that the calculated properties provide a simulated cooling curve which is closer to the experimental curve than the properties in the original database. We did not explore all of the metal properties in this study, but the modification of the sand properties was explored, together with the thermal conductivity of the steel and sand. These other measurements will be obtained in a future study.
Access status: Open Access ,
Thermal degradation of waste polyolefines and their application in blast-furnace process
(2006) Kuźnia, Monika; Magdziarz, Aneta
Nowadays about 60% of world production and consumption of plastics are polyolefines. They are used as packaging, in building engineering, automotive industry or electronic engineering. High calorific value and proper Chemical composition of polyolefines (based on carbon and hydrogen) make them ideal for use in a wide range of applications. The polyolefines can be used as a substitute for coke in blast-furnace processes. This paper outlines thermal decomposition of PE-LD, PE-HD, PP which are used in agriculture and packaging from household. Thermogravimetry (TG) and Differential Scanning Calorimetry (DSC) were used as analytical methods.