Presence Of Volatiles Research Articles

Co-pyrolysis of furniture wood with mixed plastics and waste tyres: assessment of synergistic effect on biofuel yield and product characterization under different blend ratio

Pyrolysis of waste furniture wood, mixed plastics and waste tyres was examined separately and in different combinations from the perspective of improved value products and energy production. The effect of different combinations of furniture wood, plastics and tyres on the product distribution during co-pyrolysis was analyzed. The experimental work throughout this study was performed at a temperature of 500 °C. Prior to the pyrolysis experiments, thermogravimetric analysis was done to assess the thermal degradation behavior of all selected feedstocks. During individual pyrolysis, mixed plastic wastes produced 70.6 wt% of pyrolysis liquid, which is 37.9% and 33.4% more than furniture wood and waste tyres. During co-pyrolysis, a binary blend of mixed plastics and waste tyres produced 63.3 wt% of pyrolysis liquid, which is 7.65% more than the logarithmic mean value, indicating a positive synergistic interaction on liquid production. The liquid yield of the ternary blend was observed to be as low as 54.4 wt% due to the lower volatiles present in the blend. The presence of volatiles in the feedstock is correlated with the production of liquids by individual and co-pyrolysis. For feed-flexible, more efficient, and cleaner operating systems, the increased liquid production offers crucial information. With the use of Fourier transform infrared spectroscopy (FT-IR) and gas chromatography/mass spectroscopy (GC–MS), the impact of different combinations on product characterization was investigated. The characterization study of the pyrolysis liquid obtained from mixed plastics showed the presence of different aromatic and aliphatic compounds. The findings offered viable options for efficiently utilizing waste materials, particularly plastics and tyres to improve the quality and substance of products.

Household energy consumption forecasting based on adaptive signal decomposition enhanced iTransformer network

With the presence of volatility and noise in the energy consumption data, existing energy consumption forecasting methods have difficulties in achieving satisfactory forecasting results from multiple perspectives, including accuracy, robustness, generalization, and efficiency. This study introduces a novel energy consumption forecasting framework that combines the adaptive signal decomposition method and iTransformer (ASSA-iTransformer) to tackle the above-mentioned difficulties. Each subsequence obtained by ASSA decomposition was fed into the iTransformer framework, and deep-level time series information was extracted. Compared to state-of-the-art methods across various evaluation dimensions, ASSA-iTransformer has improved the average mean absolute error (MAE) by 23.7%, root mean square error (RMSE) by 27.6%, and mean absolute percentage error (MAPE) by 16.4%. Moreover, the R2 values on five real-world household energy consumption datasets are close to 1, demonstrating overall outstanding performance.

Safe Havens Characteristics of Islamic Stock Indices During Bearish and Bullish Markets: A Case of Developed and Developing Countries

Purpose — This study examines the performance of Islamic and conventional indices during bullish (positive) and bearish (negative) markets while the economic and financial conditions are different. Design/Methodology/Approach — This study uses GARCH (1,1) and wavelet-assisted cross-spectral, cross-correlation analyses to investigate the performance of Islamic and conventional stock indices and study the presence of safe havens, which reflect low volatility in the indices during times of market turbulence, for investors during bearish and bullish periods from 2019–2021. Findings — The paper finds that there is high and persistent volatility in Islamic indices in bullish markets, while in bearish periods the Islamic indices show low volatility persistence; and conventional indices were highly volatile during crisis periods. Also, the impact of news shocks on Islamic indices was intense before COVID-19, while after that news, shocks had a high impact on the conventional indices. The wavelet coherence analysis shows that there is high coherency between Islamic and conventional indices in developed countries but in developing countries, the opposite prevails. Originality/Value — The study is the first to use both Generalised Autoregressive Conditional Heteroskedasticity (GARCH) and wavelet coherence models for examining Islamic and conventional stock indices during bearish and bullish markets, especially in the COVID-19 pandemic era. Practical Implications — The results conclude that there are safe havens present in Islamic indices in both developing and developed countries, especially the United States (US), the United Kingdom (UK), India, and Indonesia, while in other countries the presence is weak. Both GARCH and wavelet coherence models show the same results regarding the presence of volatility and safe havens for investors in different countries.

Fe-rich X-ray amorphous material records past climate and persistence of water on Mars

X-ray amorphous material comprises 15-73 wt.% of sedimentary rocks and eolian sediments in Gale crater. This material is variably siliceous and iron rich but aluminum poor. The presence of volatiles is consistent with the existence of incipient weathering products. To better understand the implications of this material for past aqueous conditions on Mars, here we investigate X-ray amorphous material formation and longevity within terrestrial iron rich soils with varying ages and environmental conditions using bulk and selective dissolution methods, X-ray diffraction, and transmission electron microscopy. Results indicate that in situ aqueous alteration is required to concentrate iron into clay-size fraction material. Cooler climates promote the formation and persistence of X-ray amorphous material whereas warmer climates promote the formation of crystalline secondary phases. Iron rich X-ray amorphous material formation and persistence on Mars are therefore consistent with past cool and relatively wet environments followed by long-term cold and dry conditions.

Impact of oxygen scavenger, temperature, and packaging materials on freshness quality of packaged green teas during storage

AbstractGreen tea is renowned for its exceptional freshness; nevertheless, preserving its freshness poses a formidable challenge during storage due to its susceptibility to environmental factors. However, the effect of storage factors on freshness quality of green tea remains unclear, particularly with a lack of research studies regarding aroma quality and associated volatiles. In this study, we investigated the effects of oxygen scavenger, temperature, and packaging materials on freshness quality of packaged green teas during storage. The sensory freshness and corresponding volatile metabolites of the samples were investigated; the sensory‐chemical changes among packaged green teas during storage under different treatments were further explored. The freshness preservation in packaged green teas can be effectively achieved through the implementation of low‐temperature storage, packaging with oxygen scavenger and utilizing packaging with minimal oxygen permeability. A total of 151 volatile compounds were detected in all samples, among which 104 volatiles were identified as key contributors for distinguishing sample groups under 3 different treatments. The presence of volatiles with green, spicy, minty, and vegetable notes was found to be positively correlated with high freshness quality observed in packaged green tea. Conversely, an increase in volatiles characterized by fruity, sweet, fatty, and alkane notes was associated with the freshness deterioration. The volatiles changes that lead to freshness deterioration occurred especially under conditions of elevated temperature and increased oxygen levels, predominantly involving fat degradation, lipid oxidation, the Maillard reaction, carotenoids degradation, and dehydration reactions. The findings provide a theoretical foundation for the advancement of storage technology in packaged green teas.

A Bilevel DEA Model for Efficiency Evaluation and Target Setting with Stochastic Conditions

The effective allocation of limited resources and the establishment of targeted goals play a pivotal role in enhancing the overall efficiency of large enterprises and organizations. To achieve optimal organizational efficiency, managers seek dynamic strategies that adapt to the constraints of limited and uncertain historical data. This paper introduces an evaluation of organizational efficiency through a stochastic framework, employing a bilevel data envelopment analysis (DEA) approach. This decision-making process is centralized within a decision-making unit (DMU) overseeing subordinate decision-making units (subDMUs). Discrete scenarios, each associated with a realization probability, define the uncertain parameters in the bilevel DEA-based model. This stochastic approach allows for recourse actions upon scenario realization leading to an enhanced overall organizational strategy. Decision-makers acting within uncertain and dynamic environments can benefit from this research since it allows the investigation of efficiency assessment under alternative scenarios in the presence of volatility and risk. The potential impact of applying this methodology varies depending on the specific domain. Although, the context of this paper focuses on banking, in general, enhancing resource allocation and target setting under stochasticity, contributes to advancing sustainability across all its three dimensions (economic, environmental, social). As mentioned earlier, the practical application of our approach is demonstrated via a case study in the banking sector.

An experimental investigation into the fate of fuel-bound N-species during fluidised bed combustion of a dried coal slime in O2/Ar mixtures

The formation of NO, NO2, N2O and N2 from fuel-bound nitrogen species during the combustion of a coal slime (CS) and its char (CS char) were investigated in a laboratory bench-scale fluidised bed reactor by tracking the N-containing gas species using a gas chromatograph and an electrochemical gas analyser. Quartz sand with a particle size fraction of 0.3–0.38 mm was used as the bed material. A stream of an Ar/O2 mixture of varying O2 concentration was used as the oxidant and fluidisation gas. The effect of operating temperature (900–1300 K), initial O2 concentration (3–8%), fuel feed rate (0.0041 g min−1 for CS, 0.0036 g min−1 for CS char) and C/O2 mole ratio (0.14–0.78) on carbon burnout, NOx, N2O and N2 formation were systematically studied. It was found that the oxidation process of CS in the fluidised bed is controlled by mass diffusion under the tested conditions. N2, N2O and NO concentrations in the flue gas during CS combustion were higher than during CS char combustion under the same experimental conditions due to the presence of the greater N content in CS (1.56%) than in CS char (1.34%). At low combustion temperatures of 900 K and 1000 K, the fuel-N was mainly converted to NO and N2O. However, as the operating temperature increased, NO and N2 became the dominating species in both the CS and CS char combustion experiments. The NO concentration increased with increasing initial O2 concentration due to enhanced oxidation of char-N. Comparing the N2 formation data during CS and CS char combustion, it is inferred that in the presence of volatile, fuel-N was preferentially converted to N2.

Seismic Tomography of Nabro Caldera, Eritrea: Insights Into the Magmatic and Hydrothermal Systems of a Recently Erupted Volcano

AbstractUnderstanding the crustal structure and the storage and movement of fluids beneath a volcano is necessary for characterizing volcanic hazard, geothermal prospects and potential mineral resources. This study uses local earthquake traveltime tomography to image the seismic velocity structure beneath Nabro, an off‐rift volcano located within the central part of the Danakil microplate near the Ethiopia‐Eritrea border. Nabro underwent its first historically documented eruption in June 2011, thereby providing an opportunity to analyze its post‐eruptive state by mapping subsurface fluid distributions. We use a catalog of earthquakes detected on a temporary seismic array using machine learning methods to simultaneously relocate the seismicity and invert for the three‐dimensional P‐ and S‐wave velocity structures (VP, VS) and the ratio between them (VP/VS). Overall, our model shows higher than average P‐ and S‐wave velocities, suggesting the presence of high‐strength, solidified intrusive magmatic rocks in the crust. We identify an aseismic region of low VP, low VS, and high VP/VS ratio at depths of 6–10 km b.s.l., interpreted as the primary melt storage region that fed the 2011 eruption. Above this is a zone of high VS, low VP, and low VP/VS ratio, representing an intrusive complex of fractured rocks partially saturated with over‐pressurized gases. Our observations identify the persistence of magma in the subsurface following the eruption, and track the degassing of this melt through the crust to the surface. The presence of volatiles and high temperatures within the shallow crust indicate that Nabro is a viable candidate for geothermal exploration.

An experimental study on the role of different void removal mechanisms in VBO processing of advanced thermoplastic composites

The current study is focused on understanding the role of different void removal mechanisms in VBO processing of advanced thermoplastic composites. For this purpose, two commercially available Carbon/Poly-Ether-Ketone-Ketone (C/PEKK) tape materials were evaluated, distinct in morphologies, such as surface roughness and fiber-matrix distribution, and physical characteristics, mainly the presence of volatiles. The VBO consolidation results proved that the void reduction and removal mechanisms varied depending on the tape material. However, restricting the void reduction mechanism to dissolution and diffusion alone. Depending on the tape material, a significant difference in the consolidation dwell time was observed to achieve <1% void content parts. Thus, indicating that despite the tapes having the same polymer matrix, they differ in their diffusion behavior. The difference in the times required for consolidation may be due to the following. Firstly, the diffusion coefficients may be different for the two tapes. Although the matrix material in both tapes is PEKK, the exact formulation is unknown. Secondly, the volume of gases, which comprises entrapped air and the volatiles that evaporate during the process, that need to be removed maybe be different.

Effect of ethanol blends, E10, E25 and E85 on sub-23 nm particle emissions and their volatile fraction at exhaust of a high-performance GDI engine over the WLTC

This study was aimed to characterize the effect of ethanol blends on sub-23 nm particles and on their volatile organic fraction from a turbocharged 1.8 L direct injection spark ignition engine. Tests were performed on the Worldwide Harmonized Light Vehicles Test Cycle. Engine was fueled with three different blends: 10, 25 and 85 %v/v of ethanol content, gasoline was used as reference fuel. An Engine Exhaust Particle Sizer was used to measure the particle number and size in the range 5.6–560 nm. Particle measure was carried out by diluting the sample gas through both a single diluter and the Dekati Engine Exhaust Diluter. The number and diameter of particles emitted from ethanol blends as well as the presence of volatiles are affected from both the specific phase of the cycle and the fuel properties. A large fraction of volatiles in the sub-23 nm range, especially in the low and extra-high phases of the test cycle, was observed whatever the fuel. Anyway, the percentage of sub-23 m particles increases as the ethanol content in the blends increases except for E85. For this blend, the greater decrease of temperature due to the stronger charge cooling effect ascribable to the larger ethanol content, deteriorates the combustion evolution contributing to the formation of large soot particles. The addition of ethanol to gasoline fuel increases the volatile organic fraction whatever the blend ratio.

The effect of economic policy uncertainty index on the Indian economy in the wake of COVID-19 pandemic

PurposeThe paper tries to analyse empirically the impact of India's economic policy uncertainty (EPU) index on different macro-economic variables of India, like import, export, interest rate, exchange rate, inflation rate and stock market during pre-COVID-19 and COVID-19 era.Design/methodology/approachAlthough there exist several works where relationship and volatility among the stock markets and macro-economic indicators during the COVID-19 pandemic have been estimated, but till now none of the studies examined the effect of EPU index on different macro-economic variables in the Indian context along with the stock market due to the outbreak of COVID-19 pandemic. This is considered a noteworthy gap and hence opens up a new dimension for examination. To get a clear picture, monthly data from January, 2012 to September, 2021 have been considered where January, 2012–February, 2020 is taken as the pre-COVID-19 period and March, 2020–September, 2021 as COVID-19 period. All the data are converted into log natural. The authors applied DCC-GARCH model to investigate the impact of EPU index on volatility of selected variables over the study period across a multivariate framework and Markov regime-switching model to examine the switching over of the variables.FindingsThe results of dynamic conditional correlation - multivariate generalized autoregressive conditional heteroskedasticity (DCC-MGARCH) model indicates the presence of volatility in the dependent variables arising out of economic policy uncertainty considering the segmentation of the study period into pre-COVID-19 and COVID-19. The results of Markov regime-switching model show the variables make a significant move from low-volatility regime to high-volatility regime due to the presence of COVID-19.Research limitations/implicationsIt can be implied that impact of EPU in terms of volatility on the Indian Stock Market will lead to unfavourable investment conditions for the prospective investors. Even, the different macro-economic variables are to suffer from the volatility arising out of EPU across a long time horizon as confirmed from the DCC-MGARCH model.Originality/valueThe study is original in nature. It adds superior values from the new and significant findings from the study empirically. Application of DCC-MGARCH model and Markov regime switching model makes the study an innovative one in terms of methodology and findings.

Resource potential of lunar permanently shadowed regions

The lunar polar regions contain permanently shadowed regions (PSRs) or local topographic depressions that never receive direct sunlight. These environments (<110 K) have the potential to cold-trap volatile materials in the form of ice, which are essential resources for exploration and industrialization of cislunar space and the Solar System. Orbital observations and those from the LCROSS impactor experiment provide evidence of the existence of water ice and other cold-trapped volatiles in PSRs; however, constraints on volatile abundance and distribution remain ambiguous as individual observations are not always in concord. Here we compile observations indicating the presence of volatiles from ten remotely sensed datasets in 65 PSRs to estimate the locations and mass of water ice deposits. Faustini, Cabeus, de Gerlache, Shoemaker, Haworth, Sverdrup, Slater, and Amundsen are likely the most resource-rich PSRs. Based on co-locations of observations indicative of surface frost and subsurface hydrogen abundance, we find that the craters with the highest potential mass in metric tons (t) of water ice include Cabeus (~11 × 106 t), Shoemaker (~5 × 106 t), Faustini (~4 × 106 t), de Gerlache (~3 × 106 t), and Haworth (~3 × 106 t). Future prospecting of lunar volatiles and water ice is contingent on filling knowledge gaps in resource potential, notably accurate measurements of grade and depth of volatiles. Our proposed ranking and estimates for resource tonnage are a tool to guide future orbital and landed missions that could accurately determine the resource potential of PSR deposits.

Sentiment, Mispricing and Excess Volatility in Presence of Institutional Investors

Sentiment, Mispricing and Excess Volatility in Presence of Institutional Investors

Measuring stock market volatility - a study in India's perspective

Volatility is an inherent characteristic of stock market. The presence of volatility provides an opportunity to earn unexpected profits by risk seeker investors and becomes a matter of diffidence among risk averse as high risk is anticipated with high return during the period of high volatility. Informed investors consider market volatility while making investment decision. Volatility is reflected due to uncertainty in stock return, price and unexpected events that can be measure through the GARCH family models. Analysis is performed on daily closing value of NSE and BSE from 1 April 2011 to 31 March 2019, extracted through the online-portal of BSE (bseindia.com) and NSE (nseindia.com) for the purpose of the present analysis. The output of the current study confers the acceptance of E-GARCH model for the purpose of predicting and forecasting the market volatility.

Give me a moment: Optimal leverage in the presence of volatility, skewness, and kurtosis

Give me a moment: Optimal leverage in the presence of volatility, skewness, and kurtosis

The effect of fluorine on reaction-rim growth dynamics in the ternary CaO-MgO-SiO2 system

AbstractGrowth of reaction rims is mainly controlled by a change in physical parameters such as pressure and temperature, a change in the chemical composition of the system, and/or by the presence of volatiles. In particular, the effect of volatiles other than water on reaction-rim growth remains poorly understood. To accurately model metamorphic and metasomatic processes, a quantification of the effect of volatiles on reaction-rim growth dynamics is necessary but hitherto missing.In this study, reaction rims were experimentally grown in a series of piston-cylinder experiments in the ternary CaO-MgO-SiO2 system at 1000 °C and 1.5 GPa with 0–10 wt% F for 20 min. In the fluorine-free system, a rim sequence of wollastonite (Wo) | merwinite (Mer) | diopside (Di) | forsterite (Fo) | periclase (Per) formed, complying with the stable phase configuration at water-saturated conditions. As soon as 0.1 wt% F was introduced into the system, humite group minerals (HGMs) and monticellite (Mtc) appeared, resulting in the multilayer rim sequence Wo | Mer | Mtc | Fo + HGMs | Per. In experiments with fluorine concentrations ≥0.5 wt%, cuspidine (Csp) appears in the layer sequence and represents the major fluorine sink. Our data show that the addition of fluorine may stabilize the fluorine-bearing phases cuspidine and HGMs to higher temperatures, which is in agreement with previous studies (Grützner et al. 2017). However, the appearance of the nominally anhydrous minerals (NAMs) monticellite and åkermanite (Ak) at this P-T condition suggests that the addition of fluorine may also affect the stability of nominally fluorine-free minerals. This may be explained by the effect of fluorine on the Gibbs free energies of fluorine-bearing phases, which in turn affects the relative Gibbs free energies and thus the stabilities of all phases. An increase in absolute rim thickness from 11.8(21) to 105.6(22) µm (1σ standard deviations in parentheses) in fluorine free and 10 wt% F experiments, respectively, suggests that fluorine enhances absolute component mobilities and thus results in faster rim growth rates. Additionally, due to the presence of fluorine, a change in relative component mobilities results in microstructural changes such as a phase segregation of diopside and cuspidine at high-fluorine (≥3 wt% F) concentrations.These results not only imply that reaction rims may be used as a tool to infer the amount of fluorine present during metamorphic reactions but also that we need to consider the role of fluorine for a correct interpretation of the P-T-t history of metamorphic and metasomatic rocks.

Nematicidal Volatiles from Bacillus atrophaeus GBSC56 Promote Growth and Stimulate Induced Systemic Resistance in Tomato against Meloidogyne incognita.

Bacillus volatiles to control plant nematodes is a topic of great interest among researchers due to its safe and environmentally friendly nature. Bacillus strain GBSC56 isolated from the Tibet region of China showed high nematicidal activity against M. incognita, with 90% mortality as compared with control in a partition plate experiment. Pure volatiles produced by GBSC56 were identified through gas chromatography and mass spectrometry (GC-MS). Among 10 volatile organic compounds (VOCs), 3 volatiles, i.e., dimethyl disulfide (DMDS), methyl isovalerate (MIV), and 2-undecanone (2-UD) showed strong nematicidal activity with a mortality rate of 87%, 83%, and 80%, respectively, against M. incognita. The VOCs induced severe oxidative stress in nematodes, which caused rapid death. Moreover, in the presence of volatiles, the activity of antioxidant enzymes, i.e., SOD, CAT, POD, and APX, was observed to be enhanced in M. incognita-infested roots, which might reduce the adverse effect of oxidative stress-induced after infection. Moreover, genes responsible for plant growth promotion SlCKX1, SlIAA1, and Exp18 showed an upsurge in expression, while AC01 was downregulated in infested plants. Furthermore, the defense-related genes (PR1, PR5, and SlLOX1) in infested tomato plants were upregulated after treatment with MIV and 2-UD. These findings suggest that GBSC56 possesses excellent biocontrol potential against M. incognita. Furthermore, the study provides new insight into the mechanism by which GBSC56 nematicidal volatiles regulate antioxidant enzymes, the key genes involved in plant growth promotion, and the defense mechanism M. incognita-infested tomato plants use to efficiently manage root-knot disease.

Variations in Seismic Wave Speed and VP/VS Ratio in the North American Lithosphere

AbstractSeismic wave speed is controlled by a number of factors, including temperature and chemical composition, as well as the presence of volatiles and partial melt. Tomography provides a powerful constraint on wave speed variations, but if only VP or VS variations are imaged, it is challenging to separate the competing effects of these factors and make a full interpretation of seismic anomalies. In this study, we generate models of variations in the VP/VS ratio, which introduce new constraints on geologic structures, compositions, and processes. We invert P and S wave arrival times, as well as Rayleigh wave phase velocities, utilizing the sensitivity of Rayleigh waves to both VP and VS to form mutually constrained but independent models of VP and VS structure at lithospheric depths below the continental United States and Southeastern Canada. From this we can examine variations in VP/VS, highlighting a distinct pattern of anomalies which are less readily observed in VP or VS alone. A clustering analysis is performed to relate 1‐D profiles of wave speed as a function of depth to tectonic provinces. While the first‐order structure of VP and VS appears to be dominated by the thermal contrast between the Eastern and Western United States, the strongest control over VP/VS ratio perturbations within the mantle lithosphere appears to be the presence of melt. Certain higher‐VP/VS anomalies within the cratonic interior may reflect compositional anomalies and variations in Moho structure. This work provides a continental‐scale framework for future quantitative analyses of thermal and compositional heterogeneity, and for targeted geologic interpretation.

Implications of the overconfidence bias in presence of private information: Evidence from MENA stock markets

AbstractThis paper extends the empirical literature on overconfidence by investigating the implications of this bias on the trading activity and the market volatility for different levels of private information. Using individual data for 10 MENA stock markets, we found a positive unidirectional causal relation from market return to trading volume in most markets, indicating that overconfident investors attribute past market gains to their own talent in selecting securities and trade later as if they had generated these gains. Consistent with the hypothesis of the investors' overreaction to private information, we found that the trading activity becomes more excessive as the level of private information increases. Moreover, the overconfidence helps explain the observed excessive volatility in presence of high level of private information.

Compositional and textural variations of columbite-group minerals from beryl-columbite pegmatites in the Maršíkov District, Bohemian Massif, Czech Republic: Magmatic versus hydrothermal evolution

ABSTRACT We studied compositional variations in columbite group minerals (CGM) from several granitic pegmatites of the beryl-columbite subtype in the Maršíkov district, Silesian Domain of the Bohemian Massif, Czech Republic. The CGM are characterized by distinct zoned patterns in BSE images. Primary magmatic homogeneous to oscillatory zoning is preserved in corroded crystal cores, whereas the majority of the crystal volume is replaced by secondary complexly zoned domains formed via post-magmatic processes. The primary domains show relatively uniform evolutionary trends from core to rim, generally with steeply increasing Ta/(Ta + Nb) and negligible to slightly increasing Mn/(Mn + Fe). In contrast, the compositions of secondary CGM domains indicate a reversed evolution, with: (1) steeply decreasing Ta/(Ta + Nb) and relatively constant Mn/(Mn + Fe) characteristics for CGM in the Bienergraben and Scheibengraben pegmatites, and (2) insignificantly decreasing Ta/(Ta + Nb) and strongly decreasing Mn/(Mn + Fe) characteristics for CGM in the Schinderhübel I and Lysá Hora pegmatites. Patchy zoning and secondary evolution in CGM result from metasomatic replacement processes related to fluids. These fluids are probably late-magmatic and exsolved from the residual melt and in later stages locally mixed with external Mg-enriched fluids derived from the host rocks. The presence of volatiles (mainly H2O, F) facilitated high mobility of the elements and replacement of the early CGM. Textural characteristics and compositional variations in CGM show the complex evolution of the pegmatite system from the magmatic stage to subsolidus-hydrothermal conditions.