Changes In Chemical Composition Research Articles

Exploring the Relationship Between Electrical Characteristics and Changes in Chemical Composition and Structure of OSG Low-K Films Under Thermal Annealing

The influence of annealing temperature on the chemical, structural, and electrophysical properties of porous OSG low-k films containing terminal methyl groups was investigated. The films were deposited via spin coating, followed by drying at 200 °C and annealing at temperatures ranging from 350 °C to 900 °C. In the temperature range of 350–450 °C, thermal degradation of surfactants occurs along with the formation of a silicon-oxygen framework, which is accompanied by an increase in pore radius from 1.2 nm to 1.5 nm. At 600–700 °C, complete destruction of methyl groups occurs, leading to the development of micropores. FTIR spectroscopy reveals that after annealing at 700 °C, the concentration of silanol groups and water reaches its maximum. By 900 °C, open porosity is no longer observed, and the film resembles dense SiO2. JV measurements show that the film annealed at 450 °C exhibits minimal leakage currents, approximately 5 × 10−11 A/cm2 at 700 kV/cm. This can be attributed to the near-complete removal of surfactant residues and non-condensed silanols, along with non-critical thermal degradation of methyl groups. Leakage current models obtained at various annealing temperatures suggest that the predominant charge carrier transfer mechanism is Poole–Frenkel emission.

Devolatilization behaviour of Kolubara and Kostolac lignite (Serbia) during the combustion process: A case study

In this study the devolatization behaviour of lignite samples, of various grain sizes, on a wire mesh reactor is evaluated. Lignite samples were rapidly heated at four different temperatures (300, 500, 700 and 900 °C). The feed lignite reveals a high content of huminite, a low inertinite and liptinite contents in the Kostolac samples and a slightly higher liptinite content in the Kolubara samples. The char obtained at 300 °C and 500 °C shows slight petrographic and chemical changes. The major changes in chemical and petrographic compositions were observed in char heated at higher temperatures (700 °C and 900 °C). FTIR spectral data for both Kolubara and Kostolac lignite samples reveal a decrease in aliphatic- and oxygen­containing structures with increase in temperatures from 300 to 700 °C. The lack of aliphatic and oxygen-containing structures, the breakdown of clay minerals and negligible amount of water are detected in samples devolatilized at 900 °C where aromatic structures dominate.Huminite reflectance of initial samples confirms the low rank (lignite) of all the samples. Char of all grain sizes obtained at 300 °C and 500 °C showed very small changes in the maceral composition and reflectance value and still corresponded to lignite rank. A significant change in maceral composition and increase reflectance is observed in char obtained at 700 °C and 900 °C of all grain sizes.

Tree species selection for optimizing soil carbon storage: Insights from litter decomposition and bacterial community analysis in coastal ecosystems

Coastal wetland ecosystems are critical sinks for atmospheric carbon dioxide, playing a vital role in global carbon cycling and climate regulation. The decomposition of leaf litter plays a crucial role in the formation and stability of soil organic carbon (SOC) in these environments. This study investigated the impact of leaf litter decomposition from five tree species (Populus deltoids, Ligustrum lucidum, Taxodium 'Zhongshanshan', Hibiscus hamabo, and Nerium oleander) on SOC dynamics, humus composition, and soil bacterial community structure in a tidal flat. Litterbags were used to monitor the mass loss and changes in litter chemical composition over 270 days. The results revealed significant differences in decomposition rates among the tree species, with Nerium oleander exhibiting the fastest decomposition and Populus deltoids the slowest. Surprisingly, initial litter chemistry did not correlate with decomposition rates; however, changes in lignin and hemicellulose content during decomposition were significantly related to mass loss. Despite its rapid decomposition, Nerium oleander litter resulted in the highest accumulation of SOC, total humus, and humin compared to the other species, challenging the conventional view that slower decomposition leads to greater SOC storage. The soil microbial community structure was significantly influenced by SOC, humus, and litter components, with distinct microbial assemblages associated with each tree species. A random forest model identified key bacterial taxa, predominantly Proteobacteria, as important predictors of SOC content, highlighting the role of bacterial diversity in regulating SOC dynamics. These findings underscore the importance of considering litter quality, decomposition dynamics, and bacterial community composition in strategies aimed at enhancing soil carbon sequestration. This study suggests that selecting tree species with rapidly decomposing litter, such as Nerium oleander, in coastal plantations can be an effective management tool for optimizing soil carbon storage, offering valuable insights for mitigating climate change impacts.

AIR QUALITY IN YEREVAN IN THE CONTEXT OF CLIMATE CHANGE

Over the past five years, the atmospheric air quality in Yerevan has continued to deteriorate, primarily attributed to a significant increase in airborne dust, particularly during the hot summer months that coincide with the peak tourist season. This phenomenon reflects a complex interplay among atmospheric emissions, air quality, emission source altitudes, changes in chemical composition, solar radiation, weather patterns, and topographic conditions. Sources of dust pollution in Yerevan include industrial activities, vehicular emissions, road dust, and construction activities. Data from various administrative districts indicate that, over the past five years, concentrations of dust, nitrogen dioxide, and sulfur dioxide frequently exceed established standards. Additionally, there are unregulated static sources of dust pollution within the city. This study conducts a comparative analysis of the primary pollutants in the context of climate change and urbanization in Yerevan over the last five years. It also assesses green areas and evaluates the effectiveness of greening initiatives, while considering compliance with national legislation in the Republic of Armenia.

Allergy to aquatic biological resources as food

The review reveals the problem of allergies to fish and other highly allergenic foods. First of all, the products obtained from aquatic organisms are considered. The world production of fish of various species is discussed with the presentation of FAO statistics for recent years in this article. The role of aquaculture in the production of fish, shellfish and crustaceans is considered. In particular, the trends of fishing in the Black Sea and the growth of aquaculture production in Russia are analyzed. Generalized data indicate an increase in the importance of aquatic biological resources (ABR) in a balanced human diet. The study demonstrates the role of parvalbumin in the mechanism of development of allergies to products from ABR. Examples of other allergenic proteins that contain epitopes that trigger allergic reactions in the human body are given. The mechanism of these reactions is briefly described. Attention is drawn to cross-allergic reactions. Anthropogenic factors that can exacerbate allergies to fish products are discussed. These are pesticides, herbicides, antibiotics, detergent components, changes in chemical composition, and food storage conditions. Pseudoallergens with the ability to cause allergic reactions are also mentioned. Allergy symptoms can range from skin rashes and itching to respiratory problems and anaphylaxis. Treatment of fish allergy is similar to treatment for allergies to other foods. It includes the use of antihistamines, corticosteroids and sorbents. Heredity plays a major role in the development of allergic reactions. It is important to pay attention to the purity and quality of products, cooking methods, and also follow a diet. Due to the potentially higher cumulative toxicity of freshwater species, it is recommended that marine fish be preferred.

Analysis of research on abrasive wear of vermicular cast iron

The paper analyzes and discusses the orientations of researchers regarding the abrasive wear of vermicular cast iron. The analysis was related to the shape of graphite occurrence in cast iron, the change in the matrix and the change in chemical composition, and the impact of these changes on wear under dry and wet friction conditions. Compact graphite cast iron is tested for use in machine and device parts such as cylinders and piston rings, discs, shafts and bearings. It was found that the improvement of abrasive wear of vermicular cast iron is influenced, among others, by the shape of graphite, the alloy addition in the form of tin, as well as the change of the matrix in vermicular cast iron to an ausferritic one. Summarizing the analysis of research carried out by a number of authors, it would be necessary to continue research on the abrasion resistance of this material, and it would also be advisable to include issues related to the warping and deformation of samples as a result of heating and cooling of cast iron.

Beef tallow/high oleic sunflower oil shortenings produced by chemical interesterification optimized by response surface methodology (RSM): Effect of processing conditions on physical properties

AbstractResponse surface methodology (RSM) was used to obtain two shortenings (IEA and IEB) by chemical interesterification (CI) of beef tallow (BT) and high oleic sunflower oil (HOSFO) with melting points of 35.5°C and 38.5°C, higher OOO and SOO contents, and lower PPP, SOS, POS, and POP percentages than BT. The maximum percentage of HOSFO in the formulations and the optimum time, temperature, and catalyst concentrations to achieve the desired physicochemical properties for the shortenings were determined from the model. The shortenings were characterized, and the effects of processing and storage conditions were explored. HPLC/MS analysis showed that the mono and di‐unsaturated triacylglycerols (TAGs) had unsaturated fatty acids at the sn‐2 position. The changes in chemical composition due to the interesterification process were mostly differences in percentages more than in the type of TAGs present. IEA and IEB showed profiles of solid fat content versus temperature and G' values similar to those reported for soft and firm margarine, respectively. Under static cooling conditions, for BT, BA, BB, and IEB, the α‐form was the main polymorph, whereas the β′‐tendency increased with increasing temperature and slow cooling rate. IEA crystallized in the β′‐form between 20 and 32°C. Under dynamic cooling conditions, nucleation was impeded at fast cooling rate and promoted at slow rate as evidenced by induction times of crystallization. Interesterification decreased the MP, increased the β′ tendency that lasted at least 8 months at 25°C, and improved the nutritional value of shortening making them suitable as trans‐fat alternatives.

ТРАНСПОРТНЫЕ КОРИДОРЫ ЦЕНТРАЛЬНОЙ АЗИИ В СОЦИАЛЬНО-ЭКОЛОГИЧЕСКОМ ИЗМЕРЕНИИ

The article examines the socio-ecological aspects of creating transport corridors in Central Asia in the modern context. The region's unique geographical position has long attracted attention, becoming a key link between East and West, particularly along the historical Silk Road. In this regard, the environmental optimization of transport corridors is crucial for sustainable regional development. However, the increase in freight traffic amplifies human impact on the environment, leading to air, water, and soil pollution, as well as changes in the soil's chemical composition and microflora. The article offers recommendations to minimize the negative effects of multimodal transport corridors on the region’s ecosystem, a necessary step toward balancing economic growth with environmental preservation.

Ecohydrological role of groundwater outflows in the functioning of the ecotone zone in Lake Jaczno, Poland

The research determined the influence of natural groundwater outflows from the spring peat bog on the water supply and its quality in Lake Jaczno. Lake Jaczno is located in the Suwalski Landscape Park (SLP) in the Podlaskie Voivodeship, north-east Poland. The research was conducted from April 2009 to October 2010 and from September 2022 to September 2023. Water samples were collected from spring areas, shallow groundwater, and from Lake Jaczno. Fieldwork involved measuring flow, temperature, water electrolytic conductivity (EC), dissolved oxygen (DO) concentration, water oxygen saturation (WS), and water reaction (pH). Chemical analyses of water samples were carried out in the laboratory. Findings indicate that groundwater, spring water, and lake water in the SLP maintain high quality, with no significant changes in chemical composition over the past decades. Additionally, the physical water parameters display low temporal variability. The EC in the tested waters oscillates around 500 μS∙cm–1. Both spring and lake waters are well oxygenated (97–100%). Biogenic element concentrations exhibit higher variability, influenced by flora development in areas with natural groundwater outflows. High oxygenation of water contributes to increased concentrations of nitrates. The analysed waters exhibited similarity in the concentration and structure of phosphorus forms. Additionally, sediment chemical parameters at Lake Jaczno suggests a buffering capacity in the transitional zones between water and land. Despite similarities in chemical composition, sediment granulometry suggests low permeability, potentially restricting exchange between groundwater and surface waters. Monitoring springs in these environments is important due to their impact on quantity and quality of water in the analysed areas.

A Holistic View of Asphalt Binder Aging under Ultraviolet Conditions: Chemical, Structural, and Rheological Characterization

Asphalt, as a key binder material in road construction, is susceptible to ultraviolet (UV) radiation-induced aging, leading to embrittlement and reduced durability. Despite the significance of UV aging, research in this area remains limited compared to that on thermal aging. This paper comprehensively reviews the current state of research on UV aging in asphalt, focusing on its mechanism, evaluation indicators, and methods to delay or avoid UV aging. The structural components, rheological properties, and aging mechanisms of asphalt are discussed. Various UV aging simulation methods, including the use of UV chambers and accelerated aging tests, are presented along with their evaluation tests such as dynamic shear rheometry, rutting tests, Fourier infrared spectroscopy, and bending beam rheology. Key indicators used to assess UV aging, including physical properties, rheological parameters, and chemical composition changes, are summarized. The mechanisms underlying UV aging, particularly the changes in asphalt’s structural components and rheological properties, are examined. The impact of factors like radiation intensity, temperature, chemical composition, and asphalt film thickness on UV aging is discussed. Additionally, various additives and modifiers, including modified bitumen, UV shielding agents, UV absorbers, antioxidants, and nanomodifiers, are reviewed for their potential to mitigate UV aging. This paper concludes by highlighting the challenges in developing standardized test equipment and evaluation criteria, the limitations of organic modifiers, and the need for further research on nanomaterials to improve asphalt’s UV aging resistance.

Physicochemical properties, structure and biological activity of ginger polysaccharide: Effect of microwave infrared dual-field coupled drying

Ginger was dried by microwave infrared dual-field coupled drying (MIDFCD). The composition, structure, physicochemical properties and biological activity of ginger polysaccharides at various stages of MIDFCD were investigated. The MIDFCD significantly impacted the chemical composition, molecular weight (Mw), microstructure, and physicochemical properties of ginger polysaccharides. However, there were no notable differences in functional group composition. The Mw and chemical composition were notably influenced by microwave-infrared exposure and prolonged drying time. The degradation of polysaccharides due to high temperatures in the later stage resulted in further decreases in Mw and alterations in monosaccharide composition. These changes in chemical composition and Mw affected thermal properties, crystallization properties, particle size, rheological properties, antioxidant capacity, and hypoglycemic activity. These findings suggest that MIDFCD enhances the quality and bioactivity of natural polysaccharides. This study offers theoretical support for MIDFCD processing and the value-added utilization of ginger.

Changes in size and chemical composition of fruits and seeds along an elevational gradient in the tropical tree Myrsine coriacea

Changes in size and chemical composition of fruits and seeds along an elevational gradient in the tropical tree Myrsine coriacea

Identification of cigarettes with different grades by using FTIR microspectroscopy

In this paper, FTIR microspectroscopy was used to identify the cigarettes of three different grades such as Jinwan cigarettes (J group), Yinxiangyipin cigarettes (Y group) and Hongsanhuan cigarettes (H group). IR spectra and peak-area ratios (A2923 /A816, A1601 /A2923, A1601/A920 and A1072/A816) revealed significant differences among H, Y and J groups, reflecting the changes in chemical compositions with increased grade. Discriminant analysis was carried out on basis of the above peak-area ratios, achieving 100% accuracy for identification of H, Y and J groups. Principal component analysis (PCA) showed that carbohydrates and proteins were closely related to the quality of the cigarettes. In addition, curve fitting further confirmed that the structure of carbohydrates underwent changes due to the quality of the cigarettes. The above results suggest that FTIR microspectroscopy can identify different grades of the cigarettes, which may be helpful for tobacco research.

Investigation of wettability and icing on the steel surface using laser surface treatment

Icing impairs normal functionality for a variety of industries and applications. Research on hydrophobic surfaces is being conducted to solve the icing problem. In this study, a hydrophobic surface was fabricated on SM490A using a nanosecond laser. The change in surface microstructure was observed. Hydrophilicity was immediately observed right after laser irradiation, and the contact angle increased over time, resulting in hydrophobicity. To explain the wettability conversion, X-Ray Photoelectron Spectroscopy (XPS) was used to observe changes in surface chemical composition and element bonding. It was observed that the level of and increased immediately after laser irradiation, resulting in surface oxidation. Since the presence of oxides has high surface energies, they contribute to super hydrophilic surfaces. Since the bond has low surface energy and the content of nonpolar bonds and increased over time, the contact angle subsequently increases over time. When the ice shape was observed after dropping a droplet on the surface, the higher contact angle specimen reduced the attached area. Therefore, the surface treatment using a nanosecond laser can produce a hydrophobic surface on the SM490A specimens so that it may solve ice adhesion problems.

Comprehensive Investigation of Homology and Heterogeneity Between Aurantii Fructus and Aurantii Fructus Immaturus Using Chemometrics Combined with Network Pharmacology.

Aurantii Fructus (AF) and Aurantii Fructus Immaturus (AFI) are distinct herbs outlined by the Chinese Pharmacopoeia. They are sourced from the same plant but harvested at different times, resulting in differences in efficacy. It is important to avoid mixing them clinically and to distinguish between the two. Furthermore, dissimilar cultivation conditions may cause variability in the quality of herbs, so it is vital to differentiate drugs from dissimilar origins. In this study, two plants, AF and AFI from different provinces, were comparatively analyzed based on High Performance Liquid Chromatography (HPLC) fingerprints and classified using chemometric methods. The results indicate that the two medicines can be clearly distinguished. Also, AF and AFI grown in different locations can be distinguished. Ten chemical markers were screened, and their variations were determined, including eriocitrin, narirutin, naringin, meranzin hydrate, naringenin, hesperidin, nobiletin, tangeretin, neohesperidin, and poncirin. Subsequent network pharmacology correlated the screened chemical components with the biological network of the organism. The material basis of the difference in efficacy of the two homologous herbs was explored from the perspective of changes in chemical composition. This study provides a reference for formulating quality evaluation standards for AF and AFI and lays a foundation for the efficacy-related quality research of the two.

The influence of 3D printing mode on the chemical composition and structure of 30HGSA steel

The authors carried out the study of the influence of 3D printing modes on the structure and chemical composition of 30HGSA steel (chromansil) samples produced by the method of additive electric arc surfacing. To study the influence of the electric arc surfacing mode on the chemical composition of the steel under study, an optical emission analysis of the samples was carried out. The influence of the surfacing mode on the resulting structure was assessed over the entire height of the deposited walls at magnifications of ×50, ×100, ×200 and ×500. Optical emission analysis identified a change in the material chemical composition associated with the loss of chemical elements. It was found that the degree of loss of C, Cr and Si increases almost linearly and is directly proportional to the surfacing heat input (Q, J/mm). The exact influence of an increase in the surfacing heat input on the Mn content was not found, but a relationship between the degree of its loss and the voltage (U, V) during surfacing of samples was identified. Microstructural studies of all samples did not reveal a large number of systemically formed structural defects characteristic of cast and welded products (pores, shrinkage cavities, etc.), which confirms the high quality of the metal in goods produced by electric arc surfacing. Analysis of micrographs taken in different areas of the samples allowed determining that the metal microstructure does not undergo significant changes under different surfacing modes; the main tendencies in changes in the structure along the height of the sample are preserved. All samples demonstrated the formation of a highly dispersed structure, regardless of the 3D printing parameters. The most favorable metal structure, suitable for subsequent use in the production of goods using additive manufacturing, was recognized as the structure of the sample deposited using mode No.5 (I=160A, U=24V, Q=921.6J/mm). This mode can be used for further study of the problems of additive electric arc surfacing of 30HGSA steel.

Methods of Processing Dental Chromium-Cobalt Alloys for Production of Metal Frameworks Faced with Ceramics to Obtain the Best Mechanical Properties.

BACKGROUND Modern prosthetic technologies make it possible to fabricate prosthetic restorations without material loss and to make prosthetic restorations with complex geometric shapes in a relatively simple way. One such technology is selective laser melting (SLM), or additive manufacturing of metal materials, better known as 3D printing from metal or selective laser melting, but currently the most commonly used method is casting. The present study investigated use of dental chromium-cobalt alloys for prosthetic bridges and compared methods of processing dental chromium-cobalt alloys to obtain the best mechanical properties. MATERIAL AND METHODS We used dental chromium-cobalt alloy (SCHEFTNER GMBH) for laser melting StarbondCoSEeasy Powder with grain size of 10-30 µm and StarbondCoS alloy casting, made in accordance with the European standard EN ISO 22674. SLM-made specimens and induction melted alloy castings were prepared for the study. A centrifugal casting system with induction current melting of the metal alloy was used to produce the samples. The melting and casting process is automatic and limits changes in chemical composition. RESULTS The results show that none of the samples changed their chemical composition, while the samples made by SLM had better mechanical properties. CONCLUSIONS The SLM technique makes it possible to produce restorations faster and cheaper without any loss of quality compared to restorations made with the casting technique. Casting technology reduces mechanical properties, but still provides good mechanical properties.

Seismic discontinuity in the Martian crust possibly caused by water-filled cracks

Recent seismic data acquired by the InSight lander have revealed seismic discontinuities in the Martian crust that have been interpreted as sharp transitions in porosity or chemical composition. Here we propose an alternative model in which the transition from dry cracks to water-filled cracks could explain the observed seismic discontinuity in the Martian crust. Our model can explain sharp increases in seismic velocity and Vp/Vs at ∼10 km depth with no associated changes in porosity or chemical composition. The present model suggests the local existence of liquid water in the Martian crust, which could potentially serve as a subsurface habitat for life.

Using iron speciation to track hydrocarbon migration in bleached rocks and its implications for reservoir reconstruction

Bleaching of red rock beds by hydrocarbons can provide valuable insights for hydrocarbon migration and reservoir transformation. This study investigated the bleaching effects of hydrocarbons on various rock types in the Dushanzi mud volcanic area. Bedrock and bleached samples of different lithologies, including mudstone, sandy mudstone and sandstone, were systematically collected and analyzed for their iron species, mineralogical and chemical compositions using Mössbauer spectroscopy, X-ray diffraction and X-ray fluorescence, respectively. The results indicate that the iron species of the studied samples were dominated by para-Fe3+ (from 44% to 76%), with variable contents of mag-Fe3+, para-Fe2+ and pyr-Fe2+. When compared to the related unbleached rocks, the bleached rocks exhibited a higher proportion of reduced Fe (para-Fe2+ and pyr-Fe2+). The pyr-Fe2+ in the sandstones and sandy mudstones was significantly higher than that of the mudstone interlayers. The observed variations in iron species were consistent with changes in mineralogical and chemical compositions, which can be correlated with the petrological properties of rocks. The increase of quartz and decrease of feldspar and carbonates in the bleached rocks could be attributed to the dissolution of feldspar and the subsequent secondary enlargement of quartz. Geofluids containing crude oils and natural gases preferentially dissolved K-feldspar over albite. The bleached rocks had a significant decrease in the proportion of kaolinite and a slight decrease in the proportion of chlorite, while the proportions of smectite and illite were increased. The dissolution of K-feldspar could provide sufficient K+ for the formation of illite, and the appearance of smectite in the bleached samples might be related to the dissolution of albite in an alkaline environment. The dissolution of carbonates and feldspar, along with the transformation of clay minerals, had a notable positive effect on the formation of secondary porosity, facilitating hydrocarbon migration. These findings provide valuable insights into the interactions between hydrocarbons and different lithologies, informing the impact of hydrocarbon migration on reservoir reconstruction in similar geological settings.

Anatomy of a fumarole field: drone remote-sensing and petrological approaches reveal the degassing and alteration structure at La Fossa cone, Vulcano, Italy

Abstract. Hydrothermal alteration and mineralization processes can affect the physical and chemical properties of volcanic rocks. Aggressive acidic degassing and fluid flow often also lead to changes in the appearance of a rock, such as changes in surface coloration or intense bleaching. Although hydrothermal alteration can have far-reaching consequences for rock stability and permeability, limited knowledge exists on the detailed structures, extent, and dynamic changes that take place near the surface of hydrothermal venting systems. By integrating drone-based photogrammetry with mineralogical and chemical analyses of rock samples and surface gas flux, we investigate the structure of the evolving volcanic degassing and alteration system at the La Fossa cone on the island of Vulcano, Italy. Our image analysis combines principal component analysis (PCA) with image classification and thermal analysis through which we identify an area of approximately 70 000 m2 that outlines the maximum extent of hydrothermal alteration effects at the surface, represented by a shift in rock color from reddish to gray. Within this area, we identify distinct gradients of surface coloration and temperature that indicate a local variability in the degassing and alteration intensity and define several structural units within the fumarole field. At least seven such larger units of increased activity could be constrained. Through mineralogical and geochemical analysis of samples from the different alteration units, we define a relationship between surface appearance in drone imagery and the mineralogical and chemical composition. Gradients in surface color from reddish to gray correlate with a reduction in Fe2O3 from up to 3.2 % in the unaltered regime to 0.3 % in the altered regime, and the latter coincides with the area of increased diffuse acid gas flux. As the pixel brightness increases towards higher alteration gradients, we note a loss of the initial (igneous) mineral fraction and a change in the bulk chemical composition with a concomitant increase in sulfur content from close to 0 % in the unaltered samples to up to 60 % in samples from the altered domains. Using this approach of combined remote-sensing and in situ analyses, we define and spatially constrain several alteration units and compare them to the present-day thermally active surface and degassing pattern over the main crater area. The combined results permit us to present a detailed anatomy of the La Fossa fumarole field, including high-temperature fumaroles and seven larger units of increased alteration intensity, surface temperature, and variably intense surface degassing. Importantly, we also identify apparently sealed surface domains that prevent degassing, likely as a consequence of mineral precipitation from degassing and alteration processes. By assessing the thermal energy release of the identified spatial units quantitatively, we show that thermal radiation of high-temperature fumaroles accounts for < 50 % of the total thermal energy release only and that the larger part is emitted by diffuse degassing units. The integrated use of methods presented here has proven to be a useful combination for a detailed characterization of alteration and activity patterns of volcanic degassing sites and has the potential for application in alteration research and for the monitoring of volcanic degassing systems.