Mixture Of Alumina Research Articles

Exergy and energy analysis on the performance of high thermal conductivity material in PV/T system: An experimental approach

The energy loss of any system might be affects the performance. This paper focuses on the investigation of 10E: Exergy, Energy, Environmental, Economic, Exergo-Enviro-Economic, Energo-Economic, Energo-Enviro, Exergo Economic, Enviro-Economic and Exergo-Environmental analysis. The energy loss of PV/T can be mitigated by incorporating with the mixture of Aluminium, Copper and Iron as high thermal conductivity material. Energy output per-year for the developed PV is 0.9960 kW-hour. The energy output per-year for the developed solar still is 117.913 kW-hour. The Capacity Utilisation Factor for the developed system increased from 2.77 percent to 2.91 percent compared to the conventional. The Levelized Cost of Electricity for the Conventional-Solar-Still is deemed to be 3.39 $ whereas for the developed work it is 3.46 $. The output exergy per-year for the developed PV system is 140.08 kW-hour and in developed solar-still, it is 12.798 kW-hour. Gross Carbon Reduction is observed as 94 tCO2. The Carbon-Payback-Period for the developed system is 34.72 years. The estimated cost per litre of the developed work is 0.018$, 0.016$ and 0.015$ for considering the period of 15 years, 20 years and 30 years. Overall, the 10E framework of developed PV/T system provides the significant performance.

Synthesis of high purity Ti2AlC MAX phase by combustion method through thermal explosion mode: Optimization of process parameters & evaluation of microstructure

Obtaining high-purity MAX-phase powders is a challenging issue. Therefore, in this article, the effects of two key parameters, including mechanical activation time (1, 2, and 3 h), and preheating temperature (800 and 1000 °C) were investigated on the formation mechanism of Ti2AlC MAX phase using mechanically activated (assisted) self-propagating high-temperature synthesis (MA-SHS) combustion method through thermal explosion mode. For this aim, a powder mixture of titanium, aluminum, and carbon with a stoichiometry ratio of (2:1:1) was used. Differential thermal analysis (DTA) was carried out to evaluate the effect of mechanical activation and preheating temperature of the formation temperature of the target MAX phase. Subsequently, the microstructural, phase analysis, chemical composition, and determination of surface chemical states studies were carried out through scanning electron microscopy (SEM), X-ray energy distribution spectroscopy (EDS) transmission electron microscopy (TEM), X-ray diffraction analysis (XRD), and X-ray photoelectric spectroscopy (XPS), respectively. DTA results illustrated that applying mechanical activation alters the formation temperature, which leads to an increase in the purity of the MAX phase. The quantitative measurements were carried out using the Rietveld method to determine the purity of the achieved MAX phase. The results indicated that samples subjected to 2 h of mechanical activation at a preheat temperature of 1000 °C exhibited to contain 96.1 % of Ti2AlC MAX phase, which is the highest value among other specimens and the lowest amount of secondary and oxide phases (3.9 % of TiC) during the combustion synthesis process compared to other samples.

Effect of the accelerated aging process on the thermal decomposition of LiAlH4-based composite solid propellants

In the present work, a study was carried out on the effect of the accelerated aging process on the thermal decomposition of two composite solid propellants based on ammonium perchlorate (AP) and hydroxy‑terminated polybutadiene (HTPB). The first one (CP1) was enriched with aluminum (Al) powders, while the second (CP2) contained a mixture of aluminum and lithium alanate (LiAlH4) as a high-energy fuel additive. The thermal properties of the investigated propellant samples were determined using differential scanning calorimetry (DSC) and thermogravimetry (TG) techniques. The obtained results clearly demonstrated the effect of the aging process on the thermal degradation of the aged samples compared to the unaged ones, by shifting the temperature peaks of their main decomposition step to lower temperatures with a decrease in their DSC heat release. In addition, the residual unburnt propellant was increased, particularly for the complex metal hydride-based propellant. Kinetic modeling of the main thermal degradation phase, applying two advanced isoconversional methods, revealed a significant decrease in activation energy for the aged samples. Furthermore, the three-dimensional diffusion model involved during the investigated decomposition phase of the unaged samples was changed to a random nucleation model after 60 days of aging time.

Thermal Hazard Analysis of Two Non-Ideal Explosives Based on Ammonium Perchlorate/Ammonium Nitrate and Aluminium Powder.

In recent years, various kinds of civil explosive detonation accidents have occurred frequently around the world, resulting in substantial human casualties and significant property losses. It is generally believed that thermal stimulation plays a critical role in triggering the detonation of explosives; consequently, the study of the thermal hazards of explosives is of great significance to many aspects of safety emergency management practices in the production, transportation, storage, and use of explosives. It is known that the thermal stability of the ammonium perchlorate-aluminium system and the ammonium nitrate-aluminium system has been extensively investigated previously in the literature. However, there is a paucity of research on the thermal hazard characteristics of non-ideal explosives under varying oxygen balance conditions within the academic sphere. Therefore, this research focused on the study of the thermal hazards of non-ideal explosives based on thermokinetic analysis. The thermal hazards of non-ideal explosive mixtures of ammonium perchlorate and aluminium and of ammonium nitrate and aluminium were studied by thermal analysis kinetics. The thermokinetic parameters were meticulously studied through differential scanning calorimetry (DSC) analysis. The results showed that the peak reaction temperature and activation energy of the ammonium perchlorate-aluminium system were significantly higher than those of the ammonium nitrate-aluminium system. Under the condition of zero oxygen balance, the peak reaction temperature of the ammonium nitrate-aluminium system was 259 °C (heating rate 5 °C/min), and the activation energy was 84.7 kJ/mol. Under the same conditions, the peak reaction temperature and activation energy of the ammonium perchlorate-aluminium system were 292 °C (heating rate 5 °C/min) and 94.9 kJ/mol, respectively. These results indicate that the ammonium perchlorate-aluminium system has higher safety under the same thermal stimulation conditions. Furthermore, research on both non-ideal explosive systems reveals that the activation energy is at its peak under negative oxygen balance conditions, recorded at 104.2 kJ/mol (ammonium perchlorate-aluminium) and 86.2 kJ/mol (ammonium nitrate-aluminium), which indicates a higher degree of safety. Therefore, the investigation into the thermal hazards of non-ideal explosive systems under different oxygen balance conditions is of utmost importance for the enhancement and improvement of safety emergency management practices.

Conversion of tailings solvent recovery unit (TSRU) by‐products into activated carbon‐zeolite composites: Impact of fusion pre‐treatment on porosity and CO2 capture

AbstractCurrently, the oil sands industry is producing millions of tons of tailings by‐products from the tailings solvent recovery unit (TSRU) into the tailings ponds. TSRU tailings (TTs) consist of water, asphaltene, and minerals, including silica and alumina mixtures. The oil sands sector has expanded efforts to discover solutions to remove the tailings ponds due to growing public concern about the environmental effects of these ponds and stiffer government rules on their disposal. Therefore, this report studied the effect of the different methods for the conversion of the TTs into the activated carbon‐zeolite composite. The TTs were treated with activation followed by hydrothermal, either with or without fusion with NaOH at 800°C for 1 h as a pre‐treatment. Zeolite Na‐P, zeolite A, and zeolite X were identified during the different characterizations, depending on the pre‐treatment of the fusion. The result showed that the fusion with NaOH before the hydrothermal reaction was effective as it increased the porosity and adsorption of the composite. The CO2 capture capacity of the product before fusion was 0.19 mmol/g, and after fusion, it was improved to 0.486 mmol/g.

Investigation of molten fuel coolant interaction with simulated corium in sodium

In case of a hypothetical core meltdown accident in Sodium cooled Fast Reactor (SFR), corium interacts with cold pool sodium and results in Molten Fuel Coolant Interaction (MFCI). During MFCI, the corium fragments and resultant debris settle on the core catcher as a bed and continue to generate decay heat. The size and state of fragmented debris play a crucial role in post-accident heat transfer. An experimental study has been undertaken to investigate the fragmentation of simulated corium in sodium using real-time X-ray imaging. Experiments were conducted by releasing ∼400 g of molten mixture of alumina and iron at ∼2400 °C into ∼4 kg of sodium at various temperatures. The fragmentation phenomenon was acquired using a digital flat panel detector and the captured images were subjected to image analysis to extract information on melt fragmentation. Post-experiment, fragmented debris was retrieved and subjected to sieve analysis to obtain characteristics towards assessing the dominant fragmentation mechanism. Experiments were also conducted with water for identifying key differences in the fragmentation and debris characteristics. Non-energetic fragmentation, generation of fine debris, and relatively minor sodium vaporization observed in the small-scale experiments present a reduced potential for energetic interaction in sodium than that of water.

Elucidating the impact of sanitary waste on the formation of fat, oil and grease deposits in sewer systems

The accumulation of fat, oil and grease (FOG) deposits in sanitary sewer systems is a significant cause of sewer overflows, mainly due to their tendency to adhere to pipe walls. The aim of this study is to (i) develop laboratory-prepared FOG deposits using a mixture of iron (Fe) and aluminium (Al) metal ions, fatty acids, saccharides and cooked oils, in addition to various sanitary waste materials such as paper towels, wipes and pads and (ii) examine the characteristics of these FOG deposits. The goals of this study were to (i) gain a deeper understanding of the impact of sanitary waste on the formation of FOG deposits and (ii) discuss the detailed physiochemical properties of these FOG deposits. The findings revealed that FOG deposits can vary in nature, appearing as either a smooth, paste-like substance or a coarse, semi-solid material, depending on the types of waste present in the sewer. Analysis of the fatty acid profile indicated that the FOG deposits with wipes have the highest viscosity (3.2 × 104 Pa s) and larger composition of smaller chain saturated fatty acids (caprylic acid 0.64%, undecanoic acid 5.61%, lauric acid 4.65%, myristic acid 3.21% and palmitic 8.38%). In contrast, FOG deposits with Fe and Al metal impurities have higher heat resistance and thermal stability (melting point of 125 °C) and have larger composition of long chain fatty acids. Furthermore, FTIR analysis confirmed that these FOG deposits are composed of metallic salts of fatty acids, aligning with samples from sewer lines. Our results suggest that FOG deposit formation involves the aggregation of excess calcium, which compresses free fatty acid micelles, and a saponification reaction between the calcium aggregates and free fatty acids. This research illuminates the complex processes behind FOG deposit formation and their varied characteristics, providing valuable insights into potential strategies for preventing FOG-related sewer blockages.

Morphological and structural analysis of ceramic materials composite by Kaolinite and Alumina

In this work, we report the preparation, structural and electrical characterization, morphological analysis and hardness measurements of ceramic materials composed of kaolinite Al2(Si2O5(OH)4 and alumina AL2O3. Samples were prepared from mixtures of precursor oxides starting with 100% alumina and increased the kaolinite concentration on steps of 10% up to complete 100% of kaolinite. The samples were sintered by the method of solid state reaction at temperatures of 1150, 1250 and 1350 °C. We found that the alumina samples are stable at the different temperatures of synthesis. The samples of kaolinite at 100% suffer a change phase depending on the sinterization temperature, noting that at 1350 °C yields 87% mullite and 13% cristobalite. The presence of quartz was only detected in samples with 100% kaolinite for sinterization temperatures of 1150 and 1250 °C. All samples with a mixture of alumina and kaolinite showed the presence of mullite, which is increased when the content of kaolínite is high or when the sinterization temperature is increased. This allows us to infer that the introduction of alumina optimizes the process of mullite formation hy their reaction with the SiO2 that remainder from the kaolinite. The sample with 100% alumina has a Mohs hardness of about 5, and this is increased with the content of kaolinite, until a Mohs hardness of about 6 to the sample with 100% kaolinite. The dielectric constant of these materials is around 27.82.

Characterization of partial wetting by CMAS droplets using multiphase many-body dissipative particle dynamics and data-driven discovery based on PINNs

The molten sand that is a mixture of calcia, magnesia, alumina and silicate, known as CMAS, is characterized by its high viscosity, density and surface tension. The unique properties of CMAS make it a challenging material to deal with in high-temperature applications, requiring innovative solutions and materials to prevent its buildup and damage to critical equipment. Here, we use multiphase many-body dissipative particle dynamics simulations to study the wetting dynamics of highly viscous molten CMAS droplets. The simulations are performed in three dimensions, with varying initial droplet sizes and equilibrium contact angles. We propose a parametric ordinary differential equation (ODE) that captures the spreading radius behaviour of the CMAS droplets. The ODE parameters are then identified based on the physics-informed neural network (PINN) framework. Subsequently, the closed-form dependency of parameter values found by the PINN on the initial radii and contact angles are given using symbolic regression. Finally, we employ Bayesian PINNs (B-PINNs) to assess and quantify the uncertainty associated with the discovered parameters. In brief, this study provides insight into spreading dynamics of CMAS droplets by fusing simple parametric ODE modelling and state-of-the-art machine-learning techniques.

Corrosion and carburization of Ni3Al‐based superalloys in high‐temperature carbon dioxide

AbstractTo investigate the application of Ni3Al‐based superalloys in gas turbine cycle systems, this experiment exposed Ni3Al‐based superalloys to a 600°C/5 MPa environment with 99.995% pure CO2 gas. The corrosion and carburization behaviors and mechanisms were investigated in detail. The results reveal that with prolonged thermal exposure, the surface oxides of the samples tend to develop a continuous and homogeneous transition state alumina layer. This layer serves as a protective barrier, preventing the penetration and corrosion of external carbon‐containing and oxygen‐containing substances into the matrix. A small amount of carbon‐containing hazardous substances still penetrates the oxide layer or grain boundaries through highly diffusive pathways such as nanochannels, pores, and cracks, because the transition state of alumina is not completely dense. This leads to carbon deposition at the interface between the oxide layer and the matrix, where a mixture of alumina and amorphous carbon is formed at the interface.

Preparation of high performance porous SiC ceramic membrane support using zeolite and alumina as sintering additives

In-situ reaction bonded porous SiC ceramic membrane supports were successfully synthesized by economical way at 1300 °C in air using waste zeolite residue and alumina as sintering additive. The effects of additives content and sintering temperature on material, mechanical and permeabity properties were carefully investigated. The ceramics prepared at 1300 °C with a 20 % mixture of zeolite residue and alumina obtained with a very high mechanical strength of 114.85 MPa at a porosity of 28.90 vol% and exhibited pure water permeability of 1258 L.h-1.m-2.bar−1. Additionally, the support prepared in this study exhibited good chemical resistance in acid and alkali medium for long periods.The utilization of zeolite residue reduced the sintering temperature for fabrication of membrane support and provided a flexible strategy to control the mechanical performance and water permeability. The filtration and permeation results indicated that SiC membrane support prepared in this study is suitable for various applications, particularly in water treatment.

Thermal history sensing from 1000 °C to 1400 °C based on phase transformation from Y3Al5O12 and Y4Al2O9 to YAlO3 through the intensity ratio method

Thermal history sensors are valuable tools for thermal analysis of high-temperature components within aero-engines and gas turbines. However, most thermal history sensors have an upper temperature limit of ∼1200 °C, which is insufficient to meet the requirement of gas turbines. This study introduces a novel material for thermal history sensing capable of measuring temperatures up to 1400 °C. We show thermal history measurements based on the emission intensity ratio of a Eu3+-doped yttrium–aluminum mixture, whose luminescence characteristics undergo irreversible changes when exposed to high temperature. The primary mechanism is the decrease of the symmetry ratio owing to the phase transformation from YAG (Y3Al5O12), YAM (Y4Al2O9) to YAP (YAlO3) utilizing the combination reaction of YAP induced by heat-treatment. The intensity ratio between 5D0→7F1 and 5D0→7F2 exhibits a monotonic decrease from 1.3 to 0.4 as the heat-treatment temperature increases from 1000 °C to 1400 °C. Moreover, we demonstrate that the irreversible change in intensity ratio after heat treatment remains insensitive to exposure time and oxygen partial pressure. Thus, the Eu3+-doped yttrium-aluminum mixture is a promising material for manufacturing high-temperature thermal history sensors.

Thermal Explosion in a Powder Mixture of Aluminum with Nickel Preactivated in a Low-Energy Laboratory Mill

Thermal Explosion in a Powder Mixture of Aluminum with Nickel Preactivated in a Low-Energy Laboratory Mill

Synthesis of Oxynitride Composites during Combustion of a Ferrosilicon–Natural Mineral–Aluminum Mixture in Nitrogen

Synthesis of Oxynitride Composites during Combustion of a Ferrosilicon–Natural Mineral–Aluminum Mixture in Nitrogen

ПЕРСПЕКТИВНАЯ ТЕХНОЛОГИЯ УТИЛИЗАЦИИ АЛЮМИНИЙСОДЕРЖАЩИХ ПОЛИМЕРНЫХ ОТХОДОВ

According to the Ministry of Natural Resources and Environment of the Russian Federation, about 70 million tonnes of solid municipal waste are generated annually in Russia, which contain up to 50% of polymer packaging material that has a negative impact on the environment. The amount of waste increases every year by more than 3%, destroying the fragile ecological balance in nature. Along with this there is a problem with utilisation of polymer multi-component wastes, of which there are more than 400 different types, differing from each other by compositions and technologies of processing and utilisation. Recycling of polymer wastes acquires topical importance not only from the point of view of environmental protection, but also due to the fact that in conditions of polymer raw materials deficit plastic wastes become a powerful raw material and energy resource. In order to prevent negative impact on the environment and rational use of natural resources the technology of multi-component aluminium-containing polymer waste recycling has been developed. The technological line was designed and implemented by the limited liability company "ReDevelopment". The initial raw material is complex two-layer blisters from medicines, representing a cellular plate of polymer with glued aluminium foil. In the course of operation of the technological line for processing aluminium-containing polymer waste, two types of products are formed: powder from a mixture of aluminium and polymer waste and powder of plastic waste based on different polymers. Aluminium powder is used to form aluminium briquettes, which are marketable products.

Solvent-targeted recovery of all major materials in beverage carton packaging waste

Liquid packaging boards are widely used for beverage packaging, but their complex composition poses challenges for recycling. These composites are occasionally recycled through hydropulping. However, this method only allows for partial recovery of the paperboard and produces a reject mixture of aluminium, plastics, and residual paper fiber. This study demonstrates the first process to purify all main components of beverage carton packaging waste derived from a commercial pulp mill using solvent-targeted recycling with multiple green solvents, such as p-cymene and ionic liquids. By utilizing this solvent-based process, all major components from the waste were recycled to their original forms in excellent purity, particularly aluminum—an essential industrial metal typically obtained through energy-intensive methods. Furthermore, the solvents used in our material recycling system can be recycled in high purity and reused in the fractionation process. The recovered paper fiber could be converted to the versatile platform chemical levulinic acid in good yield.

Aluminum tantalum oxide thin films deposited at low temperature by pulsed direct current reactive magnetron sputtering for dielectric applications

This research aims at studying aluminum tantalum oxide thin films (AlxTayOz) deposited at low temperature for dielectric applications. These ternary oxide layers are synthesized at 180 °C by physical vapor deposition (PVD), specifically the mid-frequency pulsed direct current reactive magnetron sputtering. The deposition process uses targets made of a mixture of aluminum and tantalum in various proportions. Four target compositions are studied containing 95 at.%, 90 at.%, 80 at.%, and 70 at.% of aluminum, corresponding to 5 at.%, 10 at.%, 20 at.%, and 30 at.% of tantalum, respectively. The ternary oxide thin films of AlxTayOz are compared to aluminum oxide (AlxOz) and tantalum oxide (TayOz) layers produced in the same experimental conditions. The AlxTayOz thin films are dense, uniform, and amorphous regardless of the experimental conditions used in this study. Their chemical composition changes as a function of the target composition. The oxygen flow used during deposition also affects the chemical composition of the oxide layers and the deposition rate. The oxide thin films with tantalum are deposited at higher deposition rates and contain more oxygen. Tantalum also promotes the amorphization of the oxide layers. The highest dielectric strength is measured for the thin film containing a low amount of tantalum combined with a high amount of oxygen.

Cadmium Sorption on Alumina Nanoparticles and Mixtures of Alumina and Smectite: An Experimental and Modelling Study

Cadmium (Cd) is one of the most toxic transition metals for living organisms. Thus, effective measures to remediate Cd from water and soils need to be developed. Cd immobilization by alumina and mixtures of alumina and smectite have been analyzed experimentally and theoretically by sorption experiments and sorption modelling, respectively. Removal of aqueous Cd was dependent on pH and Cd concentration, being maximal for pH > 7.5. A two-site non-electrostatic sorption model for Cd sorption on alumina was developed and it successfully reproduced the experimental Cd immobilization on alumina. Cd sorption on mixtures of alumina and smectite were depending on pH, ionic strength, and alumina content in the mixture. Cd removal in mixtures increased with alumina content at high pH and ionic strength values. However, Cd sorption decreased with increasing alumina content under acidic conditions and low ionic strength. This effect was the result of alumina dissolution and the release of Al3+ into the suspension at low pH values. Modelling of Cd sorption on mixtures of alumina and smectite was performed by considering the individual Cd sorption models for alumina and smectite. It could be shown that the contributions of the individual sorption models were additive in the model for the mixtures when the competition of Al3+ with Cd2+ for cation exchange sites in smectite was included.

Tunable room-temperature ferromagnetism in RF magnetron sputtered Al2Cr2Cu2O8 thin film

Metal oxide solid solution thin films containing ternary mixtures of Alumina (Al2O3), Chromia (Cr2O3) and Cupric oxide (CuO) were successfully prepared combinatorially on FTO, quartz glass and Si substrates using radio frequency (RF) magnetron sputtering (vertical geometry; on-axis sputtering) technique with RF powers of 200 W and 100 W. XRD analysis prove the development of tetragonal phase Al2Cr2Cu2O8 in sputtering target. Al2Cr2Cu2O8 film deposited on Si wafer and quartz glass exhibits amorphous nature, whereas, the film deposited on FTO substrates exhibit crystalline structure with tetragonal phase owing to polycrystalline nature of the FTO substrates. Formation of high compositional purity with acceptable stoichiometric ratio of ternary metal oxide mixtures of Al2Cr2Cu2O8 was ascertained from the EDX spectra. The thicknesses of Al2Cr2Cu2O8 thin films are found to be in the ranges from 259 to 314 nm. Optical study showed that the optical energy band gap of Al2Cr2Cu2O8 thin film deposited on quartz substrates increased to 3.84 eV from 3.78 eV with decreasing RF power from 200 W to 100 W. The spin orbital splitting (SOS) between Cr 2p1/2 - Cr 2p3/2 and Cu 2p1/2 - Cu 2p3/2 were measured to be 9.9 eV and 19.3 eV by XPS for 200 W sputtered Al2Cr2Cu2O8 film on quartz substrate, which are the characteristics of Cr3+ and Cu2+ oxidation states, respectively. In addition, XPS analysis also confirms the presence of various oxygen vacancies in Al2Cr2Cu2O8 thin films (as-deposited and 1000 °C annealed films) on quartz substrate with RF power of 200 W, which is the most favorable condition for the presence of room temperature ferromagnetic properties observed in the present study.

Characteristics of debris resulting from simulated molten fuel coolant interactions in SFRS

Sodium cooled Fast Reactors (SFR) are built with several engineered safety features and hence a severe accident such as a core melt accident is hypothetical with a probability of <10−6/ry. However, in case of such accidents, the mixture of the molten fuel and structural materials interacts with sodium. This phenomenon is known as Molten Fuel Coolant Interaction (MFCI) and results in fragmentation of the melt due to various instabilities. The fragmented particles settle as a debris bed on the core catcher at the bottom of the reactor vessel, and continue to generate decay heat. Characteristics of the debris particles play a vital role in heat transfer from the bed and need thorough investigation. The size, shape, and physical state of the debris depend on the associated fragmentation mechanism, superheating of the melt, and sodium temperature. Experiments have been conducted by releasing simulated corium, a molten mixture of alumina and iron generated by the aluminothermy process at ∼2400 °C into liquid sodium, to study the fragmentation phenomena. After the experiment, the fragmented debris was retrieved and the particle size distribution was determined by sieve analysis. The debris was subjected to microscopic investigation for obtaining morphological characteristics. Based on the characteristics of debris, an attempt has been made to assess of fragmentation mechanism of simulated corium in sodium.