High-temperature Furnace Research Articles

Fabrication and Characterization of Mullite Reinforced MgO Added ZrO2 Ceramics

In this study, mullite (3Al2O3.2SiO2) and 10 mol % magnesia added zirconia (10 mol % MgO - 90 mol % ZrO2) ceramic powders were synthesized by conventional ceramic production processing route. The mixtures were prepared by mechanical alloying method in acetone environment with zirconia ball mill. The powders were dried in oven at 110 ºC for 24 hours before mixing. Mullite (3Al2O3.2SiO2) and 10 mol% magnesia added zirconia (MgO-ZrO2) ceramic powders were synthesized by reaction sintering from the powders made up of stoichiometric proportions of Al2O3, SiO2, MgO and ZrO2 powders after being homogenized in acetone environment in ball mills. Mullite (3Al2O3.2SiO2) and 10 mol% magnesia added zirconia (MgO-ZrO2) ceramic powders were synthesized in air at 1600 oC for 3 h and 1300 oC for 2 h, respectively. Then, the ceramic phases formed were made ready to form ceramic - ceramic composites by crushing, grinding and sieving processes. Then 0 and 10% by weight mullite (M) added magnesia doped zirconia (MgZ) mixtures were prepared by powder metallurgy method. The prepared mixtures were wet milled with zirconia ball mill for 24 h and sieved. After drying, the powders were compacted to preforms of 56x12x10 mm by uniaxial pressing at 200 MPa. The green compacts were sintered at 1500-1600 oC for 1-5 h in air conditions using a heating rate of 5 oC min-1 in a high temperature furnace. Then, microstructure (SEM), phase analysis (XRD), mechanical (hardness, 3-point bending and wear) and physical properties (% shrinkage, water absorption, porosity and density) tests were performed on the mullite added magnesia doped zirconia ceramic composites. In this study, whether there is a phase change in the ZrO2 - MgO mixture at high sintering temperatures and the effect of mullite additive on the properties of this mixture was investigated. The data obtained were presented in graphs and tables and their comments were made.

Fabrication and Characterization of Mullite Reinforced CaO Added ZrO2 Ceramics

In this study, mullite (3Al2O3.2SiO2) and 11 mol % calcia added zirconia (11 mol % CaO - 89 mol % ZrO2) ceramic powders were synthesized by conventional ceramic production processing route. The mixtures were prepared by mechanical alloying method in acetone environment with zirconia ball mill. The powders were dried in oven at 110 ºC for 24 hours before mixing. Mullite (3Al2O3.2SiO2) and 11 mol% calcia added zirconia (CaO-ZrO2) ceramic powders were synthesized by reaction sintering from the powders made up of stoichiometric proportions of Al2O3, SiO2, CaO and ZrO2 powders after being homogenized in acetone environment in ball mills. Mullite (3Al2O3.2SiO2) and 11 mol% calcia added zirconia (CaO-ZrO2) ceramic powders were synthesized in air at 1600 oC for 3 h and 1300 oC for 2 h, respectively. Then, the ceramic phases formed were made ready to form ceramic - ceramic composites by crushing, grinding and sieving processes. Then 0 and 10% by weight mullite (M) added calcia doped zirconia (CaZ) mixtures were prepared by powder metallurgy method. The prepared mixtures were wet milled with zirconia ball mill for 24 h and sieved. After drying, the powders were compacted to preforms of 56x12x10 mm by uniaxial pressing at 200 MPa. The green compacts were sintered at 1500-1600 oC for 1-5 h in air conditions using a heating rate of 5 oC min-1 in a high temperature furnace. Then, microstructure (SEM), phase analysis (XRD), mechanical (hardness, 3-point bending and wear) and physical properties (% shrinkage, water absorption, porosity and density) tests were performed on the mullite added calcia doped zirconia ceramic composites. In this study, whether there is a phase change in the ZrO2 - CaO mixture at high sintering temperatures and the effect of mullite additive on the properties of this mixture was investigated. The data obtained were presented in graphs and tables and their comments were made.

Electrochemical Features of Low Pt Electrocatalysts Deposited Over Doped Carbon Nanotubes

Carbon nanotubes (CNT) are being utilized in PEM fuel cells electrocatalysts, due to their physical and chemical characteristics. Diverse studies have been reported on their use as support of Pt to improve the metal particles dispersion, as well as to provide a higher mechanical and electrochemical stability. As it is known, the development of highly efficient electrocatalysts with low platinum loading is crucial in order to achieve the massive application of PEM fuel cells. The electronic properties of CNT can still be improved, since they play an important role in the electrochemical performance. Recently, it has been reported that the incorporation of heteroatoms to the CNT structure (i.e. N, B, F, S, Si, etc.) can change positively their properties such as stability. Also, it is expected the dopant to have an effect on the Pt nanoparticles dispersion, affecting the electrochemical activity. The bonds form with the heteroatoms, as well as their concentration within the volumetric structure of the carbon, generally influence the properties of the material and change its structural geometry. The morphology and characteristics of the materials differ for each type of doping. For example, N-doping creates hollow sections separated by one or a few graphitic layers, while S-doping produces branched morphologies. Hence, it is of great interest to take advantage of the defects created by addition of heteroatoms to the CNT structure. In this research work low-Pt over doped CNT systems were obtained and evaluated. The doped carbon nanotubes were synthesized using a modified chemical vapor deposition (M-CVD) system in a high-temperature argon flow furnace. Toluene was used as a carbon source, ferrocene as a catalytic agent, adding different precursors of the heteroatoms. Low Pt loadings were deposited over pristine and doped CNT using a colloidal methodology. The structure of the obtained materials was analyzed by X-ray diffraction and Raman spectroscopy. Also, energy dispersive X-ray spectroscopy and scanning electron microscopy studies were done in order to obtain the chemical properties and the morphology. Electrochemical impedance spectroscopy (EIS) studies were done in the presence of 0.5 M H2SO4 and at an amplitude of 10 mV at different potentials vs AgAgCl (KCl sat), within a frequency range of 100 mHz to 100 KHz, in order to analyze the conductivity of the doped CNT used as support. In addition, electrochemical evaluation was performed by cyclic and lineal voltammetry in a conventional three electrode cell, in acidic electrolyte and using Ag/AgCl (KCl sat) as reference electrode, and Pt wire as a counter. In addition, in order to compare the same analyzes were carried out on reference materials such as vulcan carbon and nanotubes without dopant (pristine). The results of an extensive physical and chemical characterization confirmed the growth of doped CNT with different heteroatoms. It was possible to establish that the morphological characteristics of the obtained doped carbon nanotubes varied, depending on the dopant. Differences on the diameter, length, as well as the graphitization degree of the structure were found. Also, it was possible to confirm the low Pt loading over the supports. The evaluation of the electrochemical properties yielded interesting differences. Hence, results obtained of low-Pt loading over doped CNT electrochemical systems, will be presented and discussed at the conference.Acknowledgments: We thank the Fund "CONACyT-SENER-Sustainability Energy" (No. 254667) for the support provided for the development of this project.

Tritium extraction in aluminum metal by heating method without melting

Tritium was extracted from tritium-contaminated aluminum samples by heating it in a high-temperature furnace at 200, 300, or 400 °C for 15 h. The extracted tritium was analyzed by using a liquid scintillation counter (LSC); the sample thicknesses were 0.4 and 2 mm. The differences in tritium extraction over time were also investigated by cutting aluminum stick samples into several pieces (1, 5, 10, and 15) with the same thickness, and subsequently heating them. The results revealed that there are most of the hydrated material based on tritium on the surface of aluminum. When the temperature was increased from 200 or 300 °C–400 °C, there are no large differences in the heating duration required for the radioactivity concentration to be lower than the MDA value. Additionally, at the same thickness, because the surface of aluminum is only contaminated to tritiated water, cutting the aluminum samples into several pieces (5, 10, and 15) did not have a substantial effect on the tritium extraction fraction at any of the applied heating temperatures (200, 300, or 400 °C). The proportion of each tritium-release materials (aluminum hydrate based on tritium) were investigated via diverse analyses (LSC, XRD, and SEM-EDS).

Extraction and analysis of planetary volatiles

<p indent="0mm">Planetary volatiles refer to material components that can be separated from a solid sample as a gas phase via physical processes such as impact and heating. On the one hand, these materials are crucial for studying the formation of the solar system and the evolution of planets and their satellites. On the other hand, they provide resources for deep space exploration. Along with the exploration of deep space in recent decades, the detection of volatiles has also advanced our understanding of the cosmos. For example, the discovery of the Moon’s polar ice has changed the impression that the Moon seriously lacks volatiles, the discovery of suspected biogenic methane on Mars has rekindled people’s hope that Mars may once have harbored life, and studies of the hydrogen isotopes in comet 67P have suggested that most of the water on Earth had come from asteroids instead of comets. The combination of pyrolysis in a high-temperature furnace with mass spectrometry is the main method used to extract and analyze volatiles from deep space. This paper summarizes the extraction methods used and the functional parameters of volatile extraction payloads in deep space exploration and compares the performance indexes of the mass spectrometers used for volatile analysis. Furthermore, this paper introduces some volatiles payloads that may be extracted and analyzed in future deep space exploration missions.

A Novel System for Growth of Single Crystals from the Melt with an Innovative New Pulling Mechanism

This paper describes a crystal growth system employing novel concepts in fabrication of a high temperature furnace, thermocouples and a novel crystal pulling mechanism. This has reduced the costs substantially, without compromising the quality of grown crystals. The core of the furnace, a wooden cylindrical dummy had been prepared with equi-spaced helicalgroves with widths equaling the diameter of the heating wire on its outer surface machined by a lathe machine. The Kanthal heating wire was wound in the groves. It was covered with a thick layer of natural clay available locally. After the clay had dried up, an electric current was passed through the heating wire and the wooden frame was burnt out. A thick layer of theclay was applied on the inner and the outer surfaces. The furnace can operate at temperatures up to about 1000 °C. The temperature was measured with a chromel-alumel thermocouple prepared by an ingenious spot-welding technique established in the laboratory. The seed holder was hanged above the melt kept in the crucible with help of a float kept in awater container, which has a small tap at the bottom. When the tap is opened the float goes down and the seed assembly goes up. In this manner a quality pulling system, without any motor has been developed and reported here. It has been possible to grow good quality crystals of potassium chloride with excellent diameter control.

Ceramic sintering furnace based on combustion of premixed natural gas in porous inert media

Development of new energy-efficient high-temperature sintering furnaces is one of the key factors for cost reduction of refractory ceramic manufacturing. In this paper, a sintering furnace in which the volume of the furnace chamber is completely filled with a packed bed of ceramic spheres, and the energy source is the premixed combustion of natural gas with atmospheric air and oxygen has been experimentally studied. The furnace design allows the use of two combustion modes: (i) filtration combustion, when the narrow reaction front (combustion wave) freely propagates through the packed bed, (ii) jet-stabilized combustion when the reaction front is stabilized near gas inlet nozzles used for supplying the fresh mixture into the packed bed. Experimental analysis of both combustion modes was performed in the ranges of specific fuel flow rate from 7·10–3 to 107·10–3 Nm3·s–1/m2, firing rate from 244 to 3724 kW/m2, fuel-to-oxidizer ratio from 0.40 to 3.30, oxygen content in the oxidizer from 21 to 30 vol%. In these ranges, the temperature of the packed bed can be controlled within 1230–2220 K. Test sintering of samples pressed from powders of MgO and Al2O3 was carried out at 2170 K. It was found that the filtration combustion mode is effective for sintering parts with a characteristic size of up to 10 mm, and the packed bed can be completely formed of samples to be sintered. Jet-stabilized combustion mode is effective for sintering large pieces. In such a case, submerging samples within the packed bed enables double fuel saving compared to the stacking of samples in a furnace chamber of a conventional free-volume design. The new furnace based on the principles of premixed combustion in porous inert media can be in demand for small-scale production of ceramic parts.

Structure and Physical Properties of Cast and Splat-Quenched CoCr0.8Cu0.64FeNi High Entropy Alloy

The article investigates the structure and physical properties of the multicomponent high-entropy alloy CoCr0.8Cu0.64FeNi in the cast and quenched state. The composition of the alloy under study is analyzed using the criteria available in the literature for predicting the phase composition of high-entropy alloys. These parameters are based on calculations of the entropy and enthalpy of mixing and also include the concentration of valence electrons, the thermodynamic parameter Ω, which takes into account the melting point, entropy of mixing, and enthalpy of mixing. Another important parameter is the difference in atomic radii between the alloy components δ. Cast samples of the CoCr0.8Cu0.64FeNi alloy of nominal composition were prepared on a Tamman high-temperature electric furnace in an argon flow using a copper mold. The weight loss during the manufacture of ingots did not exceed 1%, and the average cooling rate was ~ 102K/s. Thereafter, the cast ingot was remelted, and films were obtained from the melt. The splat quenching technique used in this work consisted of the rapid cooling of melt droplets when they collide with the inner surface of a rapidly rotating (~ 8000 rpm) hollow copper cylinder. The cooling rate, estimated from the film thickness, was ~ 106 K / s. X-ray structural analysis was performed on a DRON-2.0 diffractometer with monochromatic Cu Kα radiation. Diffraction patterns were processed using the QualX2 program. The magnetic properties of the samples were measured using a vibrating sample magnetometer at room temperature. The microhardness was measured on a PMT-3 device at a load of 50 g. In accordance with theoretical predictions confirmed by the results of X-ray diffraction studies, the structure of the alloy, both in the cast and in the quenched state, is a simple solid solution of the FCC type. The lattice parameters in the cast and liquid-quenched states are 0.3593 nm and 0.3589 nm, respectively. Measurements of the magnetic properties showed that the CoCr0.8Cu0.64FeNi alloy can be classified as soft magnetic materials. In this case, quenching from a liquid state increases the coercivity. On quenched samples, increased microhardness values were also obtained. This can be explained by internal stresses arising during hardening.

Separate physicochemical effects of CO2 on the coal char combustion: An experimental and kinetic study

The overall impact of CO2 on the coal char combustion is complicated due to the interplay between the CO2 thermal effect and chemical effect (including the gasification endothermicity, and its direct additional carbon consumption). To assess the impact of these factors on the carbon consumption process, we conduct a quantitative study on the separate physicochemical effects of CO2 through experimental and kinetic research. Two oxygen concentrations (15% and 21% O2), representing industrial boiler and air combustion environments, were selected. The experiment research on its thermal effect (evaluated by carbon conversion ratios) is performed at 1773 K in a high-temperature drop tube furnace. The chemical effect of CO2 is predicted for a 100 μm coal char particle using a self-developed char burning kinetics model. Results indicate that the carbon conversion ratios show a V-type distribution with higher CO2 concentrations, as a result of its complex physicochemical effects, with minimal carbon conversion points around the CO2 concentrations of 5–10 vol.%. The thermal effect initially increases with higher CO2 concentrations from 0 to 10 vol.%, but it declines with a further increase in CO2 concentrations, while the endothermicity effect of the gasification reaction increases with higher CO2 concentrations. The relative contribution of the endothermicity effect on the char consumption is 20.4% in the 21%O2/10CO2/N2 environment, lower than the thermal effect (29.9%), but it continuously increases and becomes the most influential inhibitory factor at higher CO2 concentrations. The strongest suppression effect of CO2 corresponds to the CO2 concentrations of 10 vol.%.

Catalytic mechanism of Na on coal pyrolysis-derived carbon black formation: Experiment and DFT simulation

Coal-derived carbon black is the main composition of PM2.5, used in the rubber industry and energy storage fields. The formation and structure control of carbon black have attracted significant attention. Alkali metals have influence on the dynamic formation of coal-derived carbon black. To analyze the mechanism of Na in the formation of carbon black, a high-temperature drop tube furnace was used to analysis of carbon black from the pyrolysis of acid-washed coal and Na-containing coal at 1250 °C. DFT was applied to simulate the stepwise inhibitory effect of Na on the polymerization of PAHs into carbon black. The results show that Na promotes the oxidative cracking of large PAHs into small PAHs during the formation of coal-derived carbon black (reaction energy barrier is reduced by 17.7%), and inhibits the condensation of small PAHs molecules to form carbon black molecules (reaction energy barrier is increased by 74.7%), which causes the length of carbon black is shortened by 14.3%, and its curvature is increased by 1.7%. Na could change the spatial structure of formed carbon black-graphite crystallites, which increases the spacing of carbon black by approximately 6.2% to 16.3%. Na enhances the electrochemical performance of carbon black by 2 to 3 times.

CFD investigation of a vertical annealing furnace for stainless steel and non-ferrous alloys strips – A comparative study on air-staged & MILD combustion

A 3D CFD modelling approach of a vertical high temperature furnace in a bright annealing line for stainless steel is presented in this study. The observed line has a maximum production rate of 4.5 tonnes per hour and an overall thermal input of 1.5 MW which is provided by gas burners. The muffle furnace is an indirect heating system equipped with flameless burners, which can operate at nominal power and in off-design. The burners are arranged in four heating zones, which can be controlled separately. Pure hydrogen is used inside the muffle as protection gas around the metal. The metal strip is modelled as a highly viscous fluid with temperature-dependent properties including the specific heat, thermal conductivity and emissivity. Good accordance with measurements from an industrial line was achieved with several values from furnace thermocouples and the transient heating characteristic of a selected strip dimension, thus, demonstrating the applicability of the CFD model for the present investigations. Further simulations were performed with air-staged combustion for an evaluation of combustion and furnace efficiency as well as the thermal load on the furnace’s components. It was found that the efficiency decreased by about 0.5% using flameless combustion. The results also showed a decreased peak temperature of about 1155 °C and a reduced heat flux of about 23.3 kW/m2 (−5%) on the muffle when Moderate or Intense Low oxygen Dilution (MILD) combustion is applied. The present methodology presents an efficient approach for investigation and optimization of indirect heated muffle type furnaces.

Effective Heat Treatment Temperature of Carbon Materials in High Temperature Furnaces: Determination by the Parameters of Raman Spectroscopy of Witness Samples

Effective Heat Treatment Temperature of Carbon Materials in High Temperature Furnaces: Determination by the Parameters of Raman Spectroscopy of Witness Samples

The Effect of Boron Addition on the corrosion behavior of Ni Cr Modental alloy prepared by powder metallurgy.

The powder metallurgy (PM) method was used to create the alloy. The sintering process was carried out in an inert high-temperature tube furnace in the presence of inert gas at a temperature of 1000 ° C for 8 hours (Argon). In this article, the effect of (B) at three wt.% (0.4,0.8,1.2) on the corrosion rate, hardness, and microstructure of alloys was examined. X-ray diffraction (XRD), open circuit potential, electrochemical tests (Tafel extrapolation method), and Macro hardness Brinell were used to study the effect of adding (B) in various amounts to alloys. Saliva was utilized as the corrosion solution for the testing. The inclusion of the alloy element (B) increased hardness and a decrease in particle size, as seen by the microstructures. Furthermore, the corrosion resistance of the master alloy improved next the addition, as shown by Corrosion potential has increased while corrosion current densities have decreased. The corrosion rate for A, A1, A2 and A3 was 14.50, 7.42, 2.03and 2.77 (mpy) respectively.

Promotional effect of silica on the combustion of nano-sized aluminum powder in carbon dioxide

This paper presents how the combustion performance of nano-sized aluminum (nAl) powder in carbon dioxide are affected by silica. The ignition and combustion performance of nAl powder with silica addition were studied by a high-temperature tube furnace. An s-type thermocouple and a high-speed motion acquisition instrument were performed to evaluate the ignition temperature, maximum combustion temperature, maximum change of rate of temperature, and combustion propagation speed. The combustion efficiency and combustion products were measured and analyzed by a gas-volumetric method and an X-ray diffraction. The results show that silica added into nAl powder can enhance its maximum combustion temperature and maximum change of rate of temperature, while its ignition temperature increases slightly. The nAl powders with addition of 6.00 wt.% and 12.00 wt.% silica present high combustion propagation speeds, especially for the latter, it has high combustion efficiency. The effect mechanism of silica on the combustion of nAl powder in carbon dioxide was discussed.

Precise determination of the effect of temperature on the density of solid and liquid iron, nickel, and tin

Abstract Density and thermal expansion coefficient of metals are fundamental characteristics to describe the equation of state. Especially for liquid metals, the reported data for density and thermal expansion coefficient vary in the literature, even at ambient pressure. To determine the density of solid and liquid metals precisely at high temperatures and ambient pressure, we have developed a high-temperature furnace. The densities of solid Sn, Ni, and Fe were determined from the sample image with an uncertainty of 0.11–0.7% in the temperature range of 285–1803 K with increments of 1–10 K. The density of solid Sn decreased linearly with increasing temperature up to 493 K, and then the decrease became drastic until the melting temperature (Tm) was reached. By contrast, for solid Ni and Fe, the densities decreased linearly with increasing temperature up to the Tm (1728 and 1813 K) without any drastic density drop near Tm. This suggests that Ni and Fe do not exhibit the “premelting effect.” The density of liquid Fe was determined with an uncertainty of 0.4–0.7% in the range of 1818–1998 K with temperature increments of 5 K. The obtained thermal expansion coefficient (α) of liquid Fe was well approximated as either a constant value of α = 2.42(1) × 10–4 K–1 or a linear function of temperature (T); α = 1.37(10) × 10–3 – [6.0(6) × 10–7]T [K–1] up to at least 2000 K.

Direct Pattern Growth of Carbon Nanomaterials by Laser Scribing on Spin-Coated Cu-PI Composite Films and Their Gas Sensor Application.

The excellent physical and chemical properties of carbon nanomaterials render them suitable for application in gas sensors. However, the synthesis of carbon nanomaterials using high-temperature furnaces is time consuming and expensive. In this study, we synthesize a carbon nanomaterial using local laser-scribing on a substrate coated with a Cu-embedded polyimide (PI) thin film to reduce the processing time and cost. Spin coating using a Cu-embedded PI solution is performed to deposit a Cu-embedded PI thin film (Cu@PI) on a quartz substrate, followed by the application of a pulsed laser for carbonization. In contrast to a pristine PI solution-based PI thin film, the laser absorption of the Cu-embedded PI thin film based on Cu@PI improved. The laser-scribed carbon nanomaterial synthesized using Cu@PI exhibits a three-dimensional structure that facilitates gas molecule absorption, and when it is exposed to NO2 and NH3, its electrical resistance changes by −0.79% and +0.33%, respectively.

CHARACTERISTICS OF NEW PROMISING BENTONITE COAL SORBENTS MODIFIED BY DIFFERENT COMPOUNDS

Introduction. Bentonite clays are traditional inexpensive and effective adsorbents that have a high potential for removing heavy metals from wastewater due to their abundance, chemical and mechanical stability, high exchange ability, and unique structural properties.Problem Statement. To obtain activated carbon, high-temperature muffle furnaces are used with the consumption of a large amount of electricity, which is economically unprofitable. In addition, the resulting sorbents must be in the form of granules or tablets, have high strength and the ability to be repeatedly used in technological processes.Purpose. Development of a method for the production of low-cost granular sorbents based on bentonite as amineral component, activated carbon, as well as natural production waste (sunflower husk, straw, sawdust, etc. as modifiers), which can be removed from the activation process to increase porosity of these materials.Materials and Methods. Angren brown coal; bentonite of the Navbakhor deposit was used as a sorbent and a basic substance for the granules formation; modifiers were sodium chloride, potassium, chopped straw, sawdust. Methods of thermal decarbonization and activation of the obtained granules under the optimal conditions (950 °С, 45 min) were applied; the bulk density, the specific surface area, pore types and their total volume was determined by optical microscopy and nitrogen adsorption methods.Results. Inexpensive hybrid bentonite-carbon sorbents in the form of high-strength granules were synthesized.The optimal ratio of the main components is Bentonite:Coal = 1 : 2, size (2.5 mm) and strength of granules (83—99%), total pore volume 0.863—1.01 cm3/g, confirmed the presence of macro-, meso- and micropores. The most promising sample has a specific surface area (Langmuir) 184 m2/g.Conclusions. The method for obtaining new effective granular carbon sorbents of low cost, having high sorption capacity relative to organic and inorganic pollutants for purification of industrial process waters has been proposed.

Buoyant-flow downward flame spread over carbon fiber reinforced plastic in variable oxygen atmospheres

This study explored the downward flame spread over carbon fiber reinforced plastic (CFRP) sheets under buoyant flow in variable oxygen concentrations. Tested CFRP sheets were fabricated by laminating two unidirectional carbon fiber (CF) sheets impregnated with epoxy resins and curing them in a high-temperature furnace. The fabricated CFRP sheets were combusted in a glovebox which allowed oxygen concentration to vary. Epoxy resin sheets were also tested to investigate the effect of CFs. SEM images of burned and unburned CFRP sheets showed that the flame spread over the CFRP sheets was driven via the pyrolysis of the impregnated epoxy resins. The limiting oxygen concentration (LOC) of the CFRP sheets was 31%, while that of the epoxy resin sheets was 19%. The difference in flammability would be produced by the different thermal inertia. Contrary to the order of flammability, the flame spread rate of the CFRP sheets was higher than that of the epoxy resin sheets in more than 31% O2. In-plane temperature distributions visualized via an IR camera suggested that the CFs conductively transferred heat from flame forward, thereby accelerating the flame spread. In other words, the CFs acted as heat conductors, such as metal cores in electrical wire fires. To predict the flame spread behaviors of the CFRP sheets, this work developed a novel simplified flame spread model that involves solid-phase heat transfer. According to the model with a simulated surface temperature profile, the analytical solution of flame spread rate was derived by formulating energy balance in each zone. When the calculated flame spread rates were compared with the measured ones, a quantitative agreement was recognized. This model would be applicable to other thermally thin high-thermal-conductivity materials as well as the CFRP sheets and therefore contribute to the fire risk assessment of such materials.

A Neural Network Model for Decision-Making with Application in Sewage Sludge Management

Wastewater treatment (WWT) is a foremost challenge for maintaining the health of ecosystems and human beings; the waste products of the water-treatment process can be a problem or an opportunity. The sewage sludge (SS) produced during sewage treatment can be considered a waste to be disposed of in a landfill or as a source for obtaining raw material to be used as a fertilizer, building material, or alternative fuel source suitable for co-incineration in a high-temperature furnace. To this concern, this study’s purpose consisted of developing a decision model, supported by an Artificial Neural Network (ANN model), allowing us to identify the most effective sludge management strategy in economic terms. Consistent with the aim of the work, the suitable SS treatment was identified, selecting for each phase of the SS treatment, an alternative available on the market ensuring energy and/or matter recovery, in line with the circular water value chain. Results show that the ANN model identifies the suitable SS treatments on multiple factors, thus supporting the decision-making and identifying the solution as per user requirements.

In situ quantification of crystallisation kinetics of plagioclase and clinopyroxene in basaltic magma: Implications for lava flow

Crystallisation is a complex process that significantly affects the rheology of magma, and thus the flow dynamics during a volcanic eruption. For example, the evolution of crystal fraction, size and shape has a strong impact on the surface crust formation of a lava flow, and accessing such information is essential for accurate modelling of lava flow dynamics. To investigate the role of crystallisation kinetics on lava flow behaviour, we performed real-time, in situ synchrotron X-ray microtomography, studying the influence of temperature-time paths on the nucleation and growth of clinopyroxene and plagioclase in an oxidised, nominally anhydrous basaltic magma. Crystallisation experiments were performed at atmospheric pressure in air and temperatures from 1250°C to 1100°C, using a bespoke high-temperature resistance furnace. Depending on the cooling regime (single step versus continuous), two different crystal phases (either clinopyroxene or plagioclase) were produced, and we quantified their growth from both global and individual 3D texture analyses. The textural evolution of charges suggests that suppression of crystal nucleation is due to changes in the melt composition with increasing undercooling and time. Using existing viscosity models, we inferred the effect of crystals on the viscosity evolution of our crystal-bearing samples to trace changes in rheological behaviour during lava emplacement. We observe that under continuous cooling, both the onsets of the pāhoehoe-‘a‘ā transition and of non-Newtonian behaviour occur within a shorter time frame. With varying both temperature and time, we also either reproduced or approached the clinopyroxene and plagioclase phenocryst abundances and compositions of the Etna lava used as starting material, demonstrating that real-time synchrotron X-ray tomography is an ideal approach to unravel the final solidification history of basaltic lavas. This imaging technology has indeed the potential to provide input into lava flow models and hence our ability to forecast volcanic hazards.