Artículos de revistas: "Aluminum (CZA)"

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Li, Yongsheng, Chunhuan Luo y Qingquan Su. "Performance of Cu/ZnO/Al2O3 Catalysts Prepared by Sol–Gel Methods on Methanol Steam Reforming". Energies 16, n.º 23 (27 de noviembre de 2023): 7803. http://dx.doi.org/10.3390/en16237803.

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Cu/ZnO/Al2O3 catalysts were prepared for online methanol steam reforming (MSR) using a conventional sol–gel method in this study. The optimal preparation conditions, including the calcination temperature, Cu loading, molar ratio of citric acid to metal ions (CA/M), and pH, were investigated. CZA50 exhibited the highest MSR activity among all catalysts. It was prepared at a calcination temperature of 350 °C; Cu, Zn, and Al molar fractions of 50%, 30%, and 20%; CA/M of 1.5; and without adjusting pH. Furthermore, a modified sol–gel method was proposed to enhance the mechanical strength of Cu/ZnO/Al2O3 catalysts by using γ-Al2O3 powders as catalyst precursors instead of aluminum nitrates. In this modified method, part of Cu2+ and Zn2+ ions were impregnated firstly on γ-Al2O3 powders, and then the remaining metal ions formed sol–gel with citric acid. MCZA-0.25 catalysts prepared by this modified method showed superior catalytic activity at an Al/(Cu+Zn) ratio of 0.25. The methanol conversion rates of CZA50, MCZA-025, and CZA-Commercial were 82.9%, 79.4%, and 74.7% at the temperature of 200 °C and methanol liquid phase space velocity (LHSV) of 1.0/h, respectively. The average crushing strength of CZA50, MCZA-0.25, and CZA-Commercial were measured as 28 N/cm, 37 N/cm, and 32 N/cm, respectively.

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Olaniyan, O. S., A. A. Olanipekun, D. A. Akeredolu, A. T. Bello y J. P. Olojede. "Determination of the Pozzolanicity of Cocoa Pod Ash at Different Temperatures". LAUTECH Journal of Civil and Environmental Studies 1, March 2018 (1 de marzo de 2018): 82–86. http://dx.doi.org/10.36108/laujoces/8102/10(0121).

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Pozzolans are siliceous or aluminous materials which possess little or no cementing property but chemically react with calcium hydroxide at ordinary temperature to form compounds possessing cementitious properties. There is paucity of information on the pozzolanicity of Cocoa Pod Ash (CPA). Hence, this study investigated the pozzolanicity of CPA. Cocoa pods were obtained from selected farms in Egba Odeda, Ogun State Nigeria. The Cocoa pods were washed, sundried and calcinated to ashes in a furnace between 600° C to 1000° C at Science Laboratory Technology Department, Federal Polytechnic Ilaro, Ogun State. Chemical analyses and X-ray Crystallography were carried out on the CPA to determine the types of oxides present and their varying percentages. The oxides were Silica (SiO,), Ferric (Fe,O,), combined percentages of Ferric and Aluminum oxides (Fe,O, and Al,O,), Calcium (CaO), Magnesium (MgO) and Sulphur (SO,). The moisture content and the Loss of Ignition (LOD) of the CPA samples were also determined.The oxides of Silicon, Ferric, Aluminium, Calcium and Magnesium oxide ranged between 6.39-8.00; 0.78 – 0.89; 1.74- 2,29; 7.15-8.42 and 4.38-5.16% respectively. Sulphur trioxide and LOI ranged 3.51- 3.78 and 27.2- 32.0%, respectively. The Xray crystallography showed that the total percentage composition of SiO, Al,O, and Fe,O, in CPA varied from 14.87-24.21%. The study showed that CPA did not satisfy the minimum 70% requirements stipulated by ASTM C618 (2005) for a pozzolan after the analysis of the oxides but it satisfied all the requirements for LOI, hence CPA is a weak pozzolan

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Walbridge, Scott, Denis Beaulieu y Federico M. Mazzolani. "Recent Development of Codes for Design of Aluminum Structures in Canada". Key Engineering Materials 710 (septiembre de 2016): 451–57. http://dx.doi.org/10.4028/www.scientific.net/kem.710.451.

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In 2011, a new chapter was added to the Canadian Highway Bridge Design Code (CAN/CSA S6) [1] enabling the design of aluminum bridge components and structures in Canada. In 2016, activities are well underway, which will result in significant modifications to the Canadian aluminum structures code: “Strength Design in Aluminum” (CAN/CSA S157) [2] and the Canadian code for welding of aluminum structures: “Welded Aluminum Construction” (CAN/CSA W59.2) [3]. This paper discusses the philosophies employed in the development and modernization of these design codes and highlights some of the major changes to these codes. In the case of CAN/CSA S6, the new aluminum chapter was basically written from scratch. However, a practical approach was employed of using material from existing codes, where appropriate (including CAN/CSA S157, the AASHTO Bridge Design Specification [4], the U.S. Aluminum Design Manual [5], and the Eurocode [6]), and organizing the chapter to resemble as closely as possible the chapter for steel bridge structures, so that designers would be relatively comfortable with the new material. In the case of CAN/CSA S157, a significant reorganization of the code contents will be occurring in the latest edition, in order to bring it closer to the Canadian steel structures code (CAN/CSA S16) [7] where possible, again to make the code more user friendly. In the case of the aluminum welding code (CAN/CSA W59.2), changes are being considered to allow the use of technologies such as friction stir welding (FSW) and post-weld treatments (e.g. peening, grinding) for improving fatigue performance. This work is being done with input from Canadian industry experts and academics, in consultation with international experts from the U.S. and Europe. It is expected that this work will lead to substantially improved design codes, resulting in significant benefits in terms of the economics and safety implications of designing aluminum structures in Canada.

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Costa, Joseane Dunga da, Jeane Cruz Portela, Phâmella Kalliny Pereira Farias, Francisco Ernesto Sobrinho, Carolina Malala Martins Souza, Thaís Cristina de Souza Lopes y Francisco Wellington Andrade Silva. "Characterization and Classification of Soils of the Terra da Esperança Settlement Project in Chapada do Apodi, Brazil". Journal of Agricultural Science 11, n.º 4 (15 de marzo de 2019): 235. http://dx.doi.org/10.5539/jas.v11n4p235.

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Soil characterization and pedological classification are essential to define its main potentials and restrictions. The objective of this work was to classify the morphological, physical, chemical, and pedological attributes of soils of the Terra da Esperança Settlement Project (TESP) in Chapada do Apodi, Brazil, and find the most sensitive attributes for distinguishing them using multivariate analysis. The research was carried out in the TESP, in the municipality of Governor Dix-Sept Rosado, state of Rio Grande do Norte, Brazil. Ten sites were chosen to open representative soil profiles: Native Forest Area 1 (NFA1), 2 (NFA2), and 3 (NFA3), Collective Area with Native Forest (CNF), Agroecological Area (AEA), Cashew crop Area (CCA) Collective Area with Pasture 1 (CAP1), and 2 (CAP2), Permanent Preservation Area (PPA), and Cajaraneira (Spondia sp.) Orchard Area (COA). Disturbed and undisturbed soil samples were collected and subjected to physical and chemical analysis for soil classification. The soils classes found were: Cambissolo Haplico Carbonatico vertissolico (NFA1), Cambissolo Haplico Carbonatico tipico (CNF, and AEA), Cambissolo Haplico Ta Eutrofico tipico (CAP2, NFA2, and COA), Cambissolo Haplico Ta Eutrofico vertissolico (NFA3), Argissolo Vermelho Distrofico latossolico (CCA), Chernossolo Rendzico Ortico saprolitico (CAP1), and Neossolo Fluvico Ta Eutrofico tipico (PPA). The material of origin of the soils contributed to the presence of a calcic horizon in the profiles NFA1, CNF, AEA, CCA (Cambissolos), and CAP1 (Chernossolos). The textural class of the soils varied from sand to clay. The Argissolo (CCA) presented acid character, high aluminum saturation, low base saturation, dystrophic character, and low cation exchange capacity, forming horizons with chemical limitations, due to its latossolico character. The most sensitive attributes for distinguishing the soil classes were related to the source material, which directly influenced the soil physical (silt and clay) and chemical (acidity, salinity, nutrient availability, and clay activity) attributes.

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Saidy, A. R., A. Haris, M. Septiana, B. J. Priatmadi, H. Ifansyah y M. Mahbub. "The improvement of available phosphorous of reclaimed-mining soils with coal fly ash and empty fruit bunches of oil palm treatments". IOP Conference Series: Earth and Environmental Science 1377, n.º 1 (1 de julio de 2024): 012115. http://dx.doi.org/10.1088/1755-1315/1377/1/012115.

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Abstract Reclaimed-mining soil (RMS) were categorized as having an acidic pH, low organic carbon (C), low available phosphorous (P), and high contents of aluminium (Al) and iron (Fe); therefore, soil ameliorants were essentially added to this soil for improving soil fertility. The purpose of the research was to measure the impact of combining empty fruit bunches of oil palm (EFBOP) and coal fly ash (CFA) on the available P of RMS. Three rates of CFA application: 0, 75, and 150 Mg ha−1 and three rates of EFBOP application: 0, 25, and 50 Mg ha−1 were organized using a completely randomized design. A 1000 g of soil was placed to an experimental pot, and then CFA and EFBOP according to the treatment were added to the pot. The mixture of soils, CFA, and EFBOP were homogenized, and then incubated at 70% water holding capacity for 45 days. Available P, total P, Al-P, Fe-P, soil pH, and exchangeable Al were quantifies following the completion of incubation period. The findings of this research indicated that available P rose from 3 mg kg−1 of control (soil without treatment) to 5-41 mg kg−1 of soils with different amounts of CFA and EFBOP addition. The application of CFA and EFBOP also resulted in increases in soil pH from 4.33 in the control to pH 4.48-6.23. Additionally, the levels of Al-P, Fe-P, and exchangeable aluminum decreased with the application of CFA and EFBOP. The findings of this study highlight the potency utilizing industrial and agricultural wastes as soil ameliorants for improving available P to support plant growth on the reclaimed-mining soils.

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6

Liu, Yang. "Thermal enhancement of the oxidation layer of micron-sized aluminum powder and its anti-oxidation performance". Cambridge Science Advance 2024, n.º 1 (27 de enero de 2024): 43–54. http://dx.doi.org/10.62852/csa/2024/5.

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Micron-sized aluminum powder, with its typical core-shell structure, exhibits oxidation behavior upon slow heating in an oxidative atmosphere that is related to the particle size of the aluminum powder. A particle size-dependent thermal response mechanism for micron-sized aluminum powder is established: a "shell-breaking eruption" thermal response mechanism. The oxide layer is thermally enhanced, and the anti-oxidation reaction behavior mechanism of the enhanced samples is studied. Aluminum powder samples, heated slowly to specific temperatures to obtain changes in the oxide layer structure, are analyzed using a thermal analyzer to compare the slow heating response behavior of aluminum powder before and after the oxidation layer changes. It was found that after thermal enhancement of the aluminum powder oxidation layer, which changed from amorphous to γ-phase and whose thickness increased to twice the original thickness, the slow oxidation process of micron-sized aluminum powder was inhibited, and the aluminum powder was completely deactivated in the slow heating response.

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7

Kissell, J. Randolph. "Recent Developments in North American Aluminum Structural Design Codes". Key Engineering Materials 710 (septiembre de 2016): 427–32. http://dx.doi.org/10.4028/www.scientific.net/kem.710.427.

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Since INALCO 2013, the two main North American aluminum structural design codes – the Canadian Standards Association’s (CSA) S157 Strength Design in Aluminum and the Aluminum Association’s Specification for Aluminum Structures – have undergone significant changes. S157’s 2015 edition is the first significant revision of the Canadian aluminum structural standard since 2005, and the 2015 update of the Specification for Aluminum Structures is the first since 2010. This paper addresses the specific changes and their trends, viewed from a larger perspective to anticipate the future direction of these codes.

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Pham Thi Mai Huong y Nguyen Thi Huong. "Study ability of protection effect of organic acids for multi-metallic anti-corrosion additive system in ethylene glycol-water coolants". Vietnam Journal of Science and Technology 62, n.º 1 (23 de febrero de 2024): 48–57. http://dx.doi.org/10.15625/2525-2518/17071.

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In this work, the electrochemical behavior of carbon steel, brass, bronze and aluminum alloys in the presence of various important organic acids (sebacic acid (SbA), terephthalic (TPA), 2-ethylhexanoic (E2C6A), and octanoic (C8A)) and the effect that these have on the growth and protectiveness of the alloys have been investigated. The results show that the presence of organic acids in the coolant increases the protective effect of the system by forming a film on the surface of the alloys. The EIS impedance results demonstrate the formation of active and passive protective layers on the surface of the alloys. The results of surveying 04 types of organic acids for the protection of different alloy substrates show that TPA and SbA acid additives are more effective than C8A and E2C5A. The additive C8A not only did not inhibit corrosion but also promoted this process strongly, especially with aluminum alloys and the TPA has the best anti-corrosion effect for steel, followed by C1 copper alloy and aluminum.

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Mold, Cottle, King y Exley. "Intracellular Aluminium in Inflammatory and Glial Cells in Cerebral Amyloid Angiopathy: A Case Report". International Journal of Environmental Research and Public Health 16, n.º 8 (24 de abril de 2019): 1459. http://dx.doi.org/10.3390/ijerph16081459.

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(1) Introduction: In 2006, we reported on very high levels of aluminium in brain tissue in an unusual case of cerebral amyloid angiopathy (CAA). The individual concerned had been exposed to extremely high levels of aluminium in their potable water due to a notorious pollution incident in Camelford, Cornwall, in the United Kingdom. The recent development of aluminium-specific fluorescence microscopy has now allowed for the location of aluminium in this brain to be identified. (2) Case Summary: We used aluminium-specific fluorescence microscopy in parallel with Congo red staining and polarised light to identify the location of aluminium and amyloid in brain tissue from an individual who had died from a rare and unusual case of CAA. Aluminium was almost exclusively intracellular and predominantly in inflammatory and glial cells including microglia, astrocytes, lymphocytes and cells lining the choroid plexus. Complementary staining with Congo red demonstrated that aluminium and amyloid were not co-located in these tissues. (3) Discussion: The observation of predominantly intracellular aluminium in these tissues was novel and something similar has only previously been observed in cases of autism. The results suggest a strong inflammatory component in this case and support a role for aluminium in this rare and unusual case of CAA.

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Begen, Deniz, Gokce Calis-Ismetoglu, Omer Yunus Gumus y Halil Ibrahim Unal. "A comparative study of coal fly and bottom ashes as sustainable electroactive vibration damping materials". Environmental Engineering Research 29, n.º 4 (22 de noviembre de 2023): 230561–0. http://dx.doi.org/10.4491/eer.2023.561.

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Coal is used in most of the power and chemical plants to meet energy needs which produce various waste ashes. Reuse of these ashes as electroactive materials has great importance for sustainable development. In this study, it was detected that the main components of coal fly (CFA) and bottom ashes (CBA) were oxides of silica (SiO2), iron (Fe2O3), aluminium (Al2O3), and magnesium (MgO), besides carbon. These are well-known electrorheological (ER) active materials. The aim of this study is to reveal dielectric and electroactive vibration damping capabilities of CFA and CBA. According to the dielectric and ER flow tests carried out in insulating silicone oil (SO), the optimum concentration of particles was determined to be 35 wt.% for both ashes. Higher ER yield stress (τy = 135 Pa), higher ER efficiency (32.8), and better viscoelastic properties (τc = 128 Pa, G' = 680 kPa) under 3.0 kV mm-1 applied electric field were obtained for 35CFA/SO suspension system compared to 35CBA/SO (τy = 125 Pa, EReff = 24.0, τc = 55 Pa, G' = 260 kPa). Although it was concluded that both ashes can be upcycled to sustainable and smart vibration damping alternative materials, better performance was observed for CFA particles.

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Baghdadi, Amirhossein, Zainuddin Sajuri y Junaidi Syarif. "Study on Microstructure and Tensile Properties of New Cu-Al Bi-Metal Tubes Versus Pure Copper Tubes". Applied Mechanics and Materials 420 (septiembre de 2013): 160–66. http://dx.doi.org/10.4028/www.scientific.net/amm.420.160.

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In recent years, heating, ventilation and air condition (HVAC) industries have attempted to find alternative materials such as aluminum for replacing copper metal because of a light weight metal with relatively lower market price compared to copper. This study characterizes microstructure and tensile properties of new Cu-Al bi-metal tubes (aluminum cladded copper (ACC) and copper cladded aluminum (CCA)) versus copper phosphorous alloy tube in order to estimate the possibility of implementing the composite tubes in heating, ventilation, and air conditioning industries. The result shows that Cu phosphorus alloy tubes has the highest tensile properties followed by CCA and ACC bi-metal tubes and different tube size does not affect the tensile properties of tube of the same type.

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Liu, Yang y Hui Ren. "Reaction mechanism of micron-sized aluminum powders in O2 and CO2 gradually heated environment". Cambridge Science Advance 2024, n.º 1 (26 de enero de 2024): 10–21. http://dx.doi.org/10.62852/csa/2024/2.

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The behavior of aluminum powders in specific oxidized environment is different from each other obviously. Thermal behaviors of micron-sized aluminum powders in different oxygenated and gradually heating environments were discussed in order to find out the oxidation mechanism. Particular attention is paid to the reaction mechanism of oxygen and carbon dioxide atmosphere. Thermogravimetric analysis and related characterization methods are used and the results demonstrated that under the certain condition, reaction process of micron-sized aluminum powders can be divided into four stages. General routes for the oxidation of micron-sized aluminum in general heating system are the same, however, itis different among the extent of reaction at the third stage in different kinds of oxidizing gas atmospheres. Gas phased products were detected during the main reaction stage under carbon dioxide by combining thermal analysis and mass spectrometry which contributes to the rupture of alumina shell and further reaction of micron-sized aluminum powders. Consequently, rapider and more complete reaction process was achieved. The increasing thickness of original alumina shell can restrict the reaction rate of aluminum powders harder at the same time.

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İlhan, Çağrı y Rıza Gürbüz. "Effects of chromic acid anodizing on fatigue behavior of 7050 T7451 aluminum alloy". Materials Testing 63, n.º 9 (1 de septiembre de 2021): 805–10. http://dx.doi.org/10.1515/mt-2021-0003.

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Abstract The effect of chromic acid anodizing (CAA) surface treatment on 7050 T7451 aluminum alloy was presented in this study in terms of fatigue behavior. CAA is a treatment against corrosion by producing aluminum oxide layer (Al2O3) at the surface. However, fatigue performance of 7050 T7451 is affected by the coating. In this study, eight different CAA processes were examined with regard to etching stage of pre-treatments by using an alkaline etchant and/or acid etchants with various immersion times. Optical microscopic examinations were applied in order to determine pitting characteristics for the selection of CAA process parameters before fatigue tests. A CAA process was selected among eight processes in terms of pitting characteristics in order to apply fatigue specimens. Four fatigue test groups were determined to investigate bare condition of 7050 T7451 and sub-stages of the CAA particularly. Constant amplitude axial fatigue tests were conducted on specimens at 91 Hz at stress ratio (R) -1 until run-out criteria, which was 106 cycles. Fatigue life reduction was determined due to pretreatments of CAA. Fracture surfaces of the specimens were examined by scanning electron microscope (SEM) to investigate morphology and crack initiation sites.

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Nirmala Shivram, Padmavat. "Assessment of Ranking of Aluminum-Coconut Shell Ash Composites Using EDAS Method". Journal on Materials and its Characterization 2, n.º 1 (1 de marzo de 2023): 48–54. http://dx.doi.org/10.46632/jmc/2/1/6.

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To overcome the difficulty in manufacturing through tools and materials, the present situation calls for the creation of engineering materials to address numerous specific difficulties. Due to attainable qualities that are notable for the components involved, "Metal Matrix Composites (MMCs)" are profitable. Research significance: AMCs are used because of their low density in comparison to aluminium alloys and their interfacial behavior. Due to their outstanding castability and significant erosion protection, AMCs have been effectively repressed in modern automotive production for the “fabrication of various segments, including cylinders, motor lids, connecting shafts, and independent casts”. Research method: The complexity in the evaluation of material assemblage is well-suited to the "multi-criteria decision-making (MCDM)" methodologies. This study ranks "aluminium-coconut shell ash (CSA) composites" using the "EDAS technique", a comparatively fresh and mathematically sophisticated "MCDM (Multi-Criteria Decision Making)" tool. Result: The result obtained by using the EDAS method shows that the rank for 1100 aluminium alloy is fifth, aluminium composite with 5% is fourth, aluminium composite with 10% is second, aluminium composite with 15% is first and aluminium composite with 20% is third.Conclusion: The article's findings indicate that among all materials taken in this research, "aluminium composite with 15% CSA" emerged as the best, followed by "aluminium composite with 10% CSA", whilst the base matrix was discovered to be the material that worked the worst in this investigation.

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Du, Yu, Hui Guo y Xing-Min Guo. "Formation of Calcium Ferrite Containing Aluminum (CFA) in Sintering of Iron Ore Fines". Minerals 14, n.º 4 (14 de abril de 2024): 400. http://dx.doi.org/10.3390/min14040400.

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Calcium ferrite containing aluminum (CFA) is a precursor of the low-temperature bonding phase in the sintering process of iron ore fines for blast furnace ironmaking. Thus, improving the formation of CFA at lower temperature is very important for saving energy, improving efficiency and production. In this paper, the formation process of CFA was investigated at 1200 °C by reactions of alumina (Al2O3), respectively with a mixture of calcium oxide (CaO) and hematite (Fe2O3) and monocalcium ferrite (CF) as a recognized initial product, as well as reaction of Al-containing hematite (Hss) with CF. The result confirmed that CF is an intermediate product formed easily in the sintering process, and it may react with excessive Fe2O3 to generate an alpha-calcium iron oxide (Ca2Fe15.50O25) as a new phase. It was found that CFA can be formed directly by reactions of CF with Hss and Ca2Fe15.50O25 with Al2O3, while the reaction of CF with Al2O3 is more helpful in generating Ca2Fe15.5O25 rather than CFA, simultaneously forming a calcium aluminum oxide (CaAl2O4, CA; CaAl4O7, CA2). It was revealed that the appearance of CA and CA2 is a main reason to hinder CFA formation in the sintering process of iron ore fines.

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Liu, Yang y Hui Ren. "Study on the oxidation mechanism of micron- and nano-sized aluminum powders influenced by alumina shell". Cambridge Science Advance 2024, n.º 1 (26 de enero de 2024): 31–42. http://dx.doi.org/10.62852/csa/2024/4.

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Thermal behaviors for aluminum particles at oxidative atmosphere gradually heating system were discussed. Heating micron- and nano-sized aluminum powders from room temperature to 1400℃ using thermal analysis method. The results showed that the reaction process for micron-sized aluminum particles can be divided into four stages which include the phase change of oxidized shell, increasing thickness of alumina shell, main broken shell oxidizing process and the phase change of alumina shell in high temperature. Thermal analysis for micro aluminum particles was carried out with shell thickness adjustments via ambient manual means. It turned out that the oxide layer thickness would have full limitation effects on the slow oxidation for micro aluminum particles with shell structure when it was increased above twice of the original thickness. The limitation effects of oxide shell thickness on the heating processes in gradually heating system were proposed. Humidity environment can make the thickness of alumina increase in a certain range when the particles are in nano-scale. Complete oxidation processes were observed but an increase of the oxidation temperature was identified.

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Moon, Ho-Jin, Jung-Hwan Lee, Joong-Hyun Kim, Jonathan C. Knowles, Yong-Bum Cho, Dong-Hoon Shin, Hae-Hyoung Lee y Hae-Won Kim. "Reformulated mineral trioxide aggregate components and the assessments for use as future dental regenerative cements". Journal of Tissue Engineering 9 (enero de 2018): 204173141880739. http://dx.doi.org/10.1177/2041731418807396.

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Mineral trioxide aggregate, which comprises three major inorganic components, namely, tricalcium silicate (C3S), dicalcium silicate (C2S), and tricalcium aluminate (C3A), is promising regenerative cement for dentistry. While mineral trioxide aggregate has been successfully applied in retrograde filling, the exact role of each component in the mineral trioxide aggregate system is largely unexplored. In this study, we individually synthesized the three components, namely, C3S, C2A, and C3A, and then mixed them to achieve various compositions (a total of 14 compositions including those similar to mineral trioxide aggregate). All powders were fabricated to obtain high purity. The setting reaction of all cement compositions was within 40 min, which is shorter than for commercial mineral trioxide aggregate (~150 min). Over time, the pH of the composed cements initially showed an abrupt increase and then plateaued (pH 10–12), which is a typical behavior of mineral trioxide aggregate. The compression and tensile strength of the composed cements increased (2–4 times the initial values) with time for up to 21 days in an aqueous medium, the degree to which largely depended on the composition. The cell viability test with rat mesenchymal stem cells revealed no toxicity for any composition except C3A, which contained aluminum. To confirm the in vivo biological response, cement was retro-filled into an extracted rat tooth and the complex was re-implanted. Four weeks post-operation, histological assessments revealed that C3A caused significant tissue toxicity, while good tissue compatibility was observed with the other compositions. Taken together, these results reveal that of the three major constituents of mineral trioxide aggregate, C3A generated significant toxicity in vitro and in vivo, although it accelerated setting time. This study highlights the need for careful consideration with regard to the composition of mineral trioxide aggregate, and if possible (when other properties are satisfactory), the C3A component should be avoided, which can be achieved by the mixture of individual components.

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Kang, Gilho y Wonjong Choi. "A Study on the Effects of Surface Energy and Topography on the Adhesive Bonding of Aluminum Alloy". Korean Journal of Metals and Materials 59, n.º 8 (5 de agosto de 2021): 567–74. http://dx.doi.org/10.3365/kjmm.2021.59.8.567.

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The bonding properties of adhesives are mainly affected by surface roughness, topography and chemical adsorption. In this paper, we studied the effects of surface pretreatment of Al 2024-T3 (bare) in terms of surface roughness, topography and surface free energy. Surface pre-treatment included solvent cleaning, FPL etching, PAA and CAA treatment. The surface energy and roughness of the aluminum surface were significantly increased by the anodizing treatment. Single lap shear and fatigue tests were performed to investigate bonding properties and durability. The evaluation revealed that the surface energy and surface roughness resulting from the aluminum surface treatment had a significant impact on bonding properties and durability. PAA treated surfaces had the highest bonding strength, and CAA treated surfaces had superior bonding retention performance in hot water or salt spray environments. The results of the fatigue test most clearly demonstrated how the surface pretreatment of the aluminum alloy differently affected bonding performance.

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Honma, Takayuki, T. Tooyama, Yuichiro Kuroki, Tomoichiro Okamoto, Masasuke Takata, Yukihiro Kanechika, Masanobu Azuma y H. Taniguchi. "Thermal Conductivity and Cathodoluminescence of AlN Ceramics Sintered with Ca₃Al₂O₆ as Sintering Additive". Advanced Materials Research 11-12 (febrero de 2006): 179–82. http://dx.doi.org/10.4028/www.scientific.net/amr.11-12.179.

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Aluminum nitride (AlN) ceramics with various amounts of Ca3Al2O6 (C3A) as a sintering additive were sintered at 1880°C for 50 h in N2 atmosphere. The thermal conductivity of AlN ceramics increased with increasing amount of C3A in the range from 0.5 to 4.8 mass%. Cathodoluminescence (CL) intensity attributed to oxygen-induced defects decreased with increasing amount of C3A. From the results, the increase of the thermal conductivity was considered to relate to the decrease of the oxygen-induced defects by increasing amount of C3A.

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Choo, Thye Foo, Mohamad Amran Mohd Salleh, Kuan Ying Kok, Khamirul Amin Matori y Suraya Abdul Rashid. "Characterization of High-Temperature Hierarchical Porous Mullite Washcoat Synthesized Using Aluminum Dross and Coal Fly Ash". Crystals 10, n.º 3 (6 de marzo de 2020): 178. http://dx.doi.org/10.3390/cryst10030178.

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Mixture of aluminum dross (AD) and coal fly ash (CFA) was used to produce high-temperature porous mullite for washcoat application. CFA is the combustion by-product of pulverized coal in a coal-fired power plant, while AD is a waste product produced in secondary aluminum refining. In this study, 80 wt% of AD and 20 wt% of CFA was used to prepare a mullite precursor (MP) via acid leaching and dry-milling. The precursor was coated on a substrate and subsequently fired at 1500 °C. The results showed that the precursor transformed to a hierarchical porous microstructure assembled by large interlocked acicular mullite crystals. The pore structures consisted of large interconnected open pores and small pores. The specific surface area of the mullite washcoat was 4.85 m2g−1 after heating at 1500 °C for 4 h. The specific surface area was compatible with the specific surface area of other high-temperature washcoats.

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Ma, Yan Long y Yi Liao. "Visual Detection of Machining Damage on Aerospace Aluminium Alloys during Manufacturing Process". Applied Mechanics and Materials 252 (diciembre de 2012): 302–5. http://dx.doi.org/10.4028/www.scientific.net/amm.252.302.

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In aerospace industry, chromic acid anodizing (CAA) has been traditionally used as a non-destructive testing (NDT) technique to detect flaws in aluminium alloys. However, with the increasing restriction on the use of chromic acid and the application of lithium-containing aluminium alloys to aircraft structures, the capability of anodizing as a NDT method is challenged. In this work, machining damage was deliberately introduced to an Al-Li-Cu alloy AA2099-T8. Then, the visibility of the machine damage after tartaric-sulphuric acid anodizing (TSAA), which is an environmentally friendly anodizing process, was studied. It is suggested that, with proper lighting condition, it is possible to replace CAA with TSAA for detecting machining damage on lithium-containing aluminium alloys during manufacturing.

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Lv, Nangui, Chenhu Sun, Xueqin Wang, Chan Wang, Yuanyuan Yue y Xiaojun Bao. "Understanding the superior NH₃-SCR activity of CHA zeolite synthesized via template-free interzeolite transformation". Inorganic Chemistry Frontiers 9, n.º 6 (2022): 1300–1312. http://dx.doi.org/10.1039/d1qi01414e.

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A highly active NH3-SCR catalyst (Cu-CHAUSY) derived from CHA-type zeolite (CHAUSY) that is synthesized via template-free interzeolite transformation from ultra-stable Y (USY) with specific silicon and aluminum configurations.

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23

Aliyu, Hassan, A. K. Mohammed, S. A. KofarBai y K. R. Muhammad. "COMPOSITIONAL AND WEATHERABILITY INDICES OF GETSO KAOLIN DEPOSITS FOR POZZOLANA PRODUCTION". FUDMA JOURNAL OF SCIENCES 8, n.º 1 (2 de marzo de 2024): 103–10. http://dx.doi.org/10.33003/fjs-2024-0801-2254.

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Kaolin is an aluminio-silicate mineral naturally distributed within the earth’s crust formed from the weathering of rich feldspartic rocks. The compositional requirements of Getso kaolin deposits for pozzolana production have been carried out. The kaolin deposits were hosted by the rhyolitic rocks of the basement complex of North-Western Nigeria. Three samples from each five locations at different depths were collected and analysed using Free Swelling Ratio (FSR), Free Swelling Index (FSI), X-Ray Fluorescence Spectrometry (XRF) and Scanning Electron Microscopy/Electron Dispersive X-Ray spectroscopy (SEM/EDS). The FSI and FSR ranged between 0-6-0.9 and 16-36 revealing non-swelling and non-expansive Kaolinitic material. The XRF results showed the average concentration of SiO2+ Al2O3+Fe2O3: point 1 (78.99 wt.%); point 2 (78.62 wt.%); point 3 (79.14 wt.%); point 4 (80.10 wt.%) and point 5 (80.0 wt.%) suggested to be classified as N pozzolana (ASTMC 618). The Fe2O3/MgO versus SiO3 indicated the samples were products of the calc-alkaline series which is an indication of light colour kaolin deposits. The computed Chemical Index of Alteration (CIA: 91.34), Chemical Index of Weatheribility (CIW: 98.13), Index of compositional variability (CIV: 0.29), Silica Modulus Ratio (SM: 1.77), Lime Silica Ratio (LSR: 0.14) and Aluminum Iron Ratio (AIR: 30.0) indicated very strong weathering intensity high matured, high silica moderate aluminum and less ferrite. The studied kaolin could be utilized for the production of pozzolana after its being beneficiated to remove the TiO2.

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24

Plateau, Jean. "Une micromosaïque sur aluminium". Cahiers d'histoire de l'aluminium 56-57, n.º 1 (2016): 124. http://dx.doi.org/10.3917/cha.056.0124.

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Frøland, Hans Otto, Mats Ingulstad, Pål Sandvik y Espen Storli. "The aluminium state: how have Norwegian governments shaped the country’s aluminium industry?" Cahiers d'histoire de l'aluminium 69, n.º 2 (2 de febrero de 2024): 86–101. http://dx.doi.org/10.3917/cha.069.0086.

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Depuis la mise en service de sa première fonderie d’aluminium en 1908, la Norvège profite naturellement d’une énergie hydroélectrique abondante et peu chère. En transformant cette énergie hydroélectrique en lingots exportables, l’aluminium est devenu l’une des plus grandes sources de revenus du pays à l’export. Par l’étude du rôle actif de l’État norvégien dans l’expansion et le développement de cette industrie au cours du siècle suivant, nous observons une large gamme de politiques et instruments relatifs aux contraintes structurelles (comme le manque de ressources et de capitaux de départ) et à des défis plus généraux (comme les barrières commerciales, la R&D, l’acquisition du savoir-faire ou les politiques de soutien aux opérations internationales). Nous soulignons le caractère durable de ces instruments politiques et intérêts gouvernementaux qui constituent le socle de la stratégie à long terme de cette industrie. Alors que l’État s’est attaqué aux contraintes et défis du secteur, en appelant notamment à plus de diversification dans la fabrication, l’industrie du pays se concentre principalement toujours, après plus d’un siècle, sur les opérations amont. Le succès se déploie à l’international depuis les années 1990.

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26

Liao, Fei y Xing-Min Guo. "The Effects of Al2O3 and SiO2 on the Formation Process of Silico-Ferrite of Calcium and Aluminum (SFCA) by Solid-State Reactions". Minerals 9, n.º 2 (10 de febrero de 2019): 101. http://dx.doi.org/10.3390/min9020101.

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The silico-ferrite of calcium and aluminum (SFCA) is a significant crystalline phase that bonds in high basicity sinter. Al2O3 and SiO2 play an important role in the formation of SFCA in the Fe2O3–CaO–SiO2–Al2O3 system, but the effect mechanism of Al2O3 and SiO2 on the formation of SFCA is unclear. To investigate this effect, sintering experiments were carried out with different temperatures and different times. It was found that the reaction of Al2O3 with CaFe2O4 (CF) as an initial product was easier to form during the calcium iron aluminum oxide (CFA) than that of SiO2 with CF to form SFC. This was due to the former directly forming to CFA while the latter initially formed Ca2SiO4 (C2S) and Ca2.5Fe15.5O25, and then SFC. It was also observed that when Al2O3 and SiO2 existed simultaneously, the Al2O3 initially reacted with CF to form CFA at 1100 °C, while the SiO2 participated in the formation of SFCA at 1150 °C without the formation of SFC. Moreover, it was understood that these were different effects in that the Al2O3 promoted the transformation from the orthorhombic crystal system to the triclinic crystal system, while the SiO2 dissolved into CFA to form the SFCA phase when Al2O3 existed.

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27

Saimoto, Shigeo, Michael R. Langille y Marek Niewczas. "Forensic Analyses of Stress-Strain Diagrams to Evaluate Contributions from Microstructure". Materials Science Forum 941 (diciembre de 2018): 2270–77. http://dx.doi.org/10.4028/www.scientific.net/msf.941.2270.

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The conventional characterization of work-hardening is to approximate the stress-strain diagram using the empirical curve-fitting of Hollomon or Voce. The new method uses the Taylor slip analyses to derive a functional form which is optimally fitted to the data. This constitutive relations analysis (CRA) duplicates the data using at least two fit loci. The fit parameters relate to the slip motion within the microstructure and hence its interpretation reveals the possible dynamic shape-change reactions. The fit-process defines a new yield stress which separates the yielding from the deformation mechanisms at large strains that breaks up into two regions separated by intersection parameters. The applications of CRA to nanovoid formation and growth leading to ductile failure, plane stress yield locus prediction using tensile tests and decoding the stress-strain diagram for age-hardened aluminum alloys have been successful. Using super-pure aluminum, this study confirms that CRA is based on crystal plasticity principles and that CRA can predict the correlation of the obstacle strength factor, α, with work-hardening, hence permitting conversion of flow stress at given strains to obstacle density. The derived results show that the inherent annihilation process and the changing strength factor are coordinated to result in a self-consistent constitutive relation.

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Lu, Xuhang, Bo Liu, Qian Zhang, Quan Wen, Shuying Wang, Kui Xiao y Shengen Zhang. "Recycling of Coal Fly Ash in Building Materials: A Review". Minerals 13, n.º 1 (23 de diciembre de 2022): 25. http://dx.doi.org/10.3390/min13010025.

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Coal fly ash (CFA) is a type of solid waste produced in the process of coal combustion, which is rich in silicon oxide, aluminum oxide and a small number of heavy metals and radioactive elements. Therefore, CFA is considered a secondary resource with high recovery value. Currently, CFA is mainly reused in the fields of building materials, mine backfilling, soil conditioners and fertilizers, among which the production of building materials is one of the most important ways to realize large-scale utilization of CFA. This paper introduces the physical and chemical properties, classification and environmental impact of CFA and summarizes the utilization status of CFA in building materials such as cement, concrete, ceramics and geopolymers, as well as the management policy of CFA. In addition, the existing problems in the utilization of CFA as a building material are analyzed, and their development prospects are discussed.

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29

Zhu, Xu Fei, Long Fei Jiang, Wei Xing Qi, Chao Lu y Ye Song. "Thermal Stability of Solid Aluminum Electrolytic Capacitors with Conductive Polyaniline Counter Electrode". Advanced Materials Research 512-515 (mayo de 2012): 1018–21. http://dx.doi.org/10.4028/www.scientific.net/amr.512-515.1018.

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To overcome the risk of electrolyte leakage and the shortcoming of higher impedance at high frequencies for the conventional aluminum electrolytic capacitor impregnated with electrolyte solutions, solid aluminum electrolytic capacitor employing conducting polyaniline (PANI) as a counter electrode was developed. The as-fabricated solid capacitors have very low impedances at high frequencies and excellent thermal stability. The superior performances can be ascribed to high conductivity and good thermal stability of the camphorsulfonic acid (CSA)-dodecylbenzenesulfonic acid (DBSA) co-doped PANI.

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30

Yao, Zhongying, Xinxin Liu, Lijun Qian, Yajun Chen, Bo Xu y Yong Qiu. "Synthesis and Characterization of Aluminum 2-Carboxyethyl-Phenyl-Phosphinate and Its Flame-Retardant Application in Polyester". Polymers 11, n.º 12 (29 de noviembre de 2019): 1969. http://dx.doi.org/10.3390/polym11121969.

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A flame retardant aluminum 2-carboxyethyl-phenyl-phosphinate (CPA-Al) was synthesized through the salification reaction. The molecular structure of CPA-Al and thermal stability were characterized by solid nuclear magnetic resonance, Fourier transform infrared spectroscopy, and thermogravimetric analysis. Subsequently, CPA-Al mixed in polyurethane was coated on polyester textile to obtain flame-retardant samples. The addition of 14.7 wt.% CPA-Al in textile sample can bring a limited oxygen index (LOI) value of 24.5%, 0 s after flame time, and the vertical burning B1 rating. Meanwhile, the incorporated CPA-Al reduced the peak heat release rate, total heat release, average effective heat of combustion, and increased the charring capacity of polyester textiles in contrast to the samples without CPA-Al. CPA-Al exerted not only its flame inhibition effect in gas phase, but also the charring and barrier effect in the condensed phase. Besides, with an increasing CPA-Al ratio in polyester textile, the contact angle gradually decreased from 123.6° to 75.6°, indicating that the surficial property of coating from hydrophobic to hydrophilic, thereby increasing the moisture permeability of polyester textile.

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31

Zimring, Carl A. "A Circular Economy? Aluminum Recycling in Historical Perspective". Cahiers d'histoire de l'aluminium 69, n.º 2 (2 de febrero de 2024): 132–45. http://dx.doi.org/10.3917/cha.069.0132.

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Cet article se concentre sur l’histoire du recyclage de l’aluminium, entre la hausse de sa production lors de la Deuxième Guerre mondiale et le début du XXI e siècle, pour évaluer les affirmations selon lesquelles le recyclage de l’aluminium constituerait une économie circulaire. Ces affirmations reposent sur des taux contemporains élevés de valorisation et de recyclage, et s’appuient sur l’histoire de la récupération des métaux secondaires, notamment avec l’augmentation des systèmes de collecte publics associés à une perception du recyclage en tant qu’activité écologique. À partir du travail de spécialistes en « Discard studies » (études des déchets) comme Samantha MacBride et Josh Lepawsky, le présent article étudie dans quelle mesure ces affirmations représentent, ou non, des efforts significatifs pour réduire les dommages environnementaux causés par la production initiale d’aluminium. La multiplication des programmes de collecte publics a participé à l’essor du recyclage au cours du dernier demi-siècle. L’utilisation plus fréquente de l’inclusion du métal dans les emballages, pour la conception industrielle et pour d’autres applications a toutefois intensifié la production initiale qui a plus que triplé à l’échelle mondiale sur cette période. Cet article conclut par un débat sur les limites du recyclage et les stratégies susceptibles de réduire la production primaire.

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Curioni, Michele, Peter Skeldon, George E. Thompson y John Ferguson. "Graded Anodic Film Morphologies for Sustainable Exploitation of Aluminium Alloys in Aerospace". Advanced Materials Research 38 (marzo de 2008): 48–55. http://dx.doi.org/10.4028/www.scientific.net/amr.38.48.

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High strength aluminium alloys are widely used in the civil and military aerospace industry due to their low weight and high mechanical properties, achieved by selected alloying elements and heat treatments. The resulting multiphase alloy system, a solid solution of alloying elements in the aluminium matrix and a variety of second phase material, requires specific anticorrosion measures in order to prevent localized corrosion, which is promoted by microgalvanic coupling between the different metallographic phases. Traditionally, the anticorrosion performances are achieved by chromic acid anodizing (CAA), followed by painting. However, environmental issues and associated costs for the disposal of chromate wastes, require the development of new approaches for anodizing of aluminium alloys. In this work, the potential for tailoring the porous anodic film morphology through the film thickness by controlled variations of the anodizing potential is inspected. The procedure developed is, in principle, applicable to any aluminium alloy in any anodizing electrolyte and results in the generation of innovative graded porous anodic film morphologies which promise improvement of anticorrosion properties and replacement of CAA .

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Mroué, Kamal H., Abdul-Hamid M. Emwas y William P. Power. "Solid-state 27Al nuclear magnetic resonance investigation of three aluminum-centered dyes". Canadian Journal of Chemistry 88, n.º 2 (febrero de 2010): 111–23. http://dx.doi.org/10.1139/v09-155.

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We report the first solid-state 27Al NMR study of three aluminum phthalocyanine dyes: aluminum phthalocyanine chloride, AlPcCl (1); aluminum-1,8,15,22-tetrakis(phenylthio)-29H,31H-phthalocyanine chloride, AlPc(SPh)4Cl (2); and aluminum-2,3-naphthalocyanine chloride, AlNcCl (3). Each of these compounds contains Al3+ ions coordinating to four nitrogen atoms and a chlorine atom. Solid-state 27Al NMR spectra, including multiple-quantum magic-angle spinning (MQMAS) spectra and quadrupolar Carr–Purcell–Meiboom–Gill (QCPMG) spectra of stationary powdered samples have been acquired at multiple high magnetic field strengths (11.7, 14.1, and 21.1 T) to determine their composition and number of aluminum sites, which were analyzed to extract detailed information on the aluminum electric field gradient (EFG) and nuclear magnetic shielding tensors. The quadrupolar parameters for each 27Al site were determined from spectral simulations, with quadrupolar coupling constants (CQ) ranging from 5.40 to 10.0 MHz and asymmetry parameters (η) ranging from 0.10 to 0.50, and compared well with the results of quantum chemical calculations of these tensors. We also report the largest 27Al chemical shielding anisotropy (CSA), with a span of 120 ± 10 ppm, observed directly in a solid material. The combination of MQMAS and computational predictions are used to interpret the presence of multiple aluminum sites in two of the three samples.

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34

Honma, Takayuki, Yuichiro Kuroki, Tomoichiro Okamoto, Masasuke Takata, Yukihiro Kanechika, Masanobu Azuma y Hitofumi Taniguchi. "Temperature Dependence of Cathodoluminescence for AlN Ceramics Sintered with Ca₃Al₂O₆". Key Engineering Materials 388 (septiembre de 2008): 261–64. http://dx.doi.org/10.4028/www.scientific.net/kem.388.261.

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Aluminum nitride ceramics were sintered with 1.0 and 4.8 mass% Ca3Al2O6 (C3A) as a sintering additive. Temperature dependence of cathodoluminescence (CL) for the ceramics was investigated in order to obtain information on lattice defects. The CL peak intensity at 3.5 eV in the ceramics sintered with 1.0 mass% C3A decreased with increasing temperature, so called thermal quenching. The maximum CL peak intensity of the ceramics sintered with 4.8 mass% C3A was much lower than that with 1.0 mass% C3A, reflecting that the oxygen-induced defect density dramatically decreased with increasing amount of C3A. In case of the ceramics sintered with 4.8 mass% C3A, the CL peak intensity at 3.4 eV showed the thermal quenching in the range of 130 - 350 K, whereas in the range of 80 - 130 K and 350 - 475 K, it increased with increasing temperature, so called “negative” thermal quenching. From the results, we suggest a presence of at least two trapping levels in the ceramics sintered with C3A.

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Ortiz-Islas, Sofia, Sergio Serna-Saldivar y Silverio García-Lara. "Constitutive Changes in Nutrients and Phytochemicals in Kernels of Aluminium-Tolerant Maize (Zea mays L.)". Crops 2, n.º 1 (25 de enero de 2022): 14–22. http://dx.doi.org/10.3390/crops2010002.

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Maize (Zea mays L.) is among the three most important food crops worldwide. Maize growth is affected by high aluminium content in acid soils, which constitute nearly 50% of the world’s cultivable area. Therefore, the cultivation of aluminium-tolerant maize hybrids could be a healthier alternative and an attractive food source in these regions. In this regard, to produce hybrids kernels, 16 inbred lines aluminium-tolerant (Al-T) and aluminium-susceptible (Al-S) maize were screened for their constitutive patterns of selected nutrients and phytochemicals. Proximate analysis, free phenolic acids (FPA) and cell wall-bound phenolic acids (CPA) contents, as well as antioxidant capacity (AOX) were assayed in the anatomical kernel parts (pericarp, endosperm, and germ). Kernels of Al-T maize contained significantly higher germ protein, oil, and fibre (2.9, 3.0, and 0.5%, respectively) than Al-S kernels (1.9, 1.8, and 0.3%, respectively). Importantly, the nutraceutical contents in terms of pericarp FPA and germ CPA were significantly higher in kernels belonging to Al-T maize (92 mg and 140 mg EGA/100 g). The highest AOX was observed in germ CPA of Al-T kernels (9.0 mmol TE/100 g). The results herein indicate that Al-tolerance mechanisms induce positive changes in the nutrients and phytochemicals; this implies that the hybrids generated using Al-T maize inbred lines could emerge as an attractive source of nutrients and phytochemicals in farming regions containing acid soils.

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Zhu, Jianjun, Guangkai Yu, Ting Liu, Kai Liu, Xinglie Lei, Ziming Su y Linyue Zhu. "Application of Copper Cladding Aluminum Composites in UHV Portable Earthing and Short-circuiting Wires". MATEC Web of Conferences 160 (2018): 01004. http://dx.doi.org/10.1051/matecconf/201816001004.

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Aiming at the heavy weight and inconvenience when carrying and installing copper earthing wires on the UHV transmission lines, in this paper, we present the use of copper clad aluminum(CCA) composite materials as a lightweight method for UHV earthing wire conductor. Theoretical calculations and tests of the fusing current in a short time for copper and CCA material are conducted. The results show that the theoretical value of the earthing wire conductor's fusing current corresponds with the test value on condition of the conductor cross section greater than 4mm2 as well as fusing time less than 1.5s. The CCA-10 earthing wires get 36.2% weight reduction compared with copper wires.

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Liu, Yang y Hui Ren. "Studies on activity and oxide shell thickness of micron-sized Mg-Al alloy powder". Cambridge Science Advance 2024, n.º 1 (26 de enero de 2024): 22–30. http://dx.doi.org/10.62852/csa/2024/3.

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The empirical formula of average oxide thickness of atomized micron-sized aluminum - magnesium alloy powder was proposed. At the same time, the influence of particle size and the ratio of magnesium on samples’ activity was studied. The phase composition, morphology, and oxidation process of the alloy powders were studied by x-ray diffraction, scanning electron microscope/energy-dispersive x-ray, respectively. Study on the change of powder activity was achieved by standard gas volumn method. The results show that the oxide thickness of the atomized micron-sized aluminum - magnesium alloy powder is positively correlated with the particle size, and the activity decreases with the increase of the particle size and the magnesium content.

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Fahdiran, Riser, Erfan Handoko, Iwan Sugihartono, Anggara Budi Susila, Esmar Budi y Setia Budi. "Structural change of aluminum thin film in the temperature range from 300 K to 1000 K". MATEC Web of Conferences 197 (2018): 02016. http://dx.doi.org/10.1051/matecconf/201819702016.

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We study the structural change of Aluminum thin film due to heat treatment. The film is heated up from room temperature of 300 K to 1000 K where it is already above melting temperature of Aluminum. Molecular dynamics simulation is employed to observe the behavior of the system since it provides atomistic detail. The structural transformation is investigated based on the structure factor and pair distribution function which indicated the broadening of the peak of crystal structure due to phase transition of the material. Atomistic information revealed the local lattice structure change based on Common Neighbor Analysis (CNA) methods.

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Rahim, Nur Liza, Syakirah Afiza Mohammed, Roshazita Che Amat, Norlia Mohamad Ibrahim, Nurhidayah Hamzah, Salmi Samsudin, Shamshinar Salehuddin, Mustaqqim Abdul Rahim y Elena Holban. "Waste to concrete material: Potential Study of Chemical Characterization of Coal Fly Ash and Bottom Ash". IOP Conference Series: Earth and Environmental Science 1216, n.º 1 (1 de julio de 2023): 012023. http://dx.doi.org/10.1088/1755-1315/1216/1/012023.

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Abstract This research focuses on the chemical properties of coal fly ash (CFA) and coal bottom ash (CBA) obtained from Sultan Azlan Shah Power Plant and compares them with the characteristics of ordinary Portland cement (OPC). Coal has been recognised as a significant fuel source in Malaysia, where it is extensively employed in the creation of steel, cement, and power. When coal is burned to create power, several different types of coal ash are created, including fly ash, bottom ash, boiler slag, and clinker. Fly and bottom ash, however, are the main coal ash waste products that have been created. In an effort to create sustainable concrete from waste, a number of studies have been carried out to ascertain the chemical characteristics of fly and bottom ash. These tests include Energy Disperse X-Ray (EDX), Mineralogy (XRD), and X-Ray Fluorescence (XRF). From the SEM result, fly ash has smaller particles and a spherical, uniform shape than bottom ash and cement. Fly and bottom ash from the Sultan Azlan Shah power plant contain a number of elements, including Silicon (Si), Aluminium (Al), Oxygen (O), Calcium (Ca), Titanium (Ti), Iron (Fe), Magnesium (Mg), Potassium (K), Carbon (C), and Sodium, according to Energy Dispersive X-Ray (EDX) test. The fly ash is primarily an amorphous material, with the presence of quartz crystalline phase (SiO2) at 24.3% and bottom ash at 31.1%, according to X-ray Diffraction (XRD) data. For the mullite phase (3AlO3.2SiO2), fly and bottom ash show results of 24.9% and 14.5%, respectively. According to an X-ray fluorescence (XRF) investigation, the main constituents of fly and bottom ash are silica, iron, and alumina. Fly ash is classified as Class F because it has a high concentration of SiO2, Al2O3, and Fe2O3 while OPC has a high CaO value. With the right composition and material preparation, CFA and CBA from the Sultan Azlan Shah Power Plant can be used as a cement replacement in concrete.

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Wang, Chuanlin, Zeping Liu, Tengteng Zhang, Yuxuan Zhang, Zehong Liu y Xianbo Zhao. "Influence of the Concentration of Seawater on the Early Hydration Properties of Calcium Sulphoaluminate (CSA) Cement: A Preliminary Study". Buildings 11, n.º 6 (6 de junio de 2021): 243. http://dx.doi.org/10.3390/buildings11060243.

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This research investigates the effect of seawater of different concentrations on the hydration process and microstructure of calcium sulphoaluminate (CSA) cement. It studies the CSA cement pastes via experiments carried out to determine the initial and final setting times, mechanical strength and chemical shrinkage with X-ray diffraction (XRD), scanning electron microscopy (SEM) and simultaneous differential thermal-thermogravimetric (DTA-TG) analysis. The DTA-TG and XRD results showed that the main hydration products were ettringite (AFt) and aluminum hydroxide in the CSA cement paste mixed with both freshwater and seawater, while a small amount of ettringite (AFt) became monosulfate (AFm) in the freshwater-mixed CSA cement. The SEM results demonstrate that seawater can improve the microstructure of CSA cement paste in the early stage of hydration (1 d) but impairs the microstructure of the CSA cement matrix in the later stage of hydration (7 d). The experimental results also indicate that a high concentration of seawater can extend the setting time, increase the chemical shrinkage and decrease the mechanical strength of CSA cement.

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41

Lambert, Olivier. "Laminer à chaud l’aluminium". Cahiers d'histoire de l'aluminium 68, n.º 1 (13 de julio de 2023): 26–45. http://dx.doi.org/10.3917/cha.068.0026.

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Le site de Constellium Neuf-Brisach est dédié à la transformation de l’aluminium. C’est un des principaux laminoirs d’Europe avec une capacité annuelle de production de près de 500 000 tonnes. Inauguré en 1967, ce site prend ses racines dans la croissance des Trente Glorieuses. Au fil des années 1950, les usages de l’aluminium se développent rapidement et les producteurs français, regroupés au sein de la Compagnie générale du duralumin et du cuivre (Cegédur) décident d’installer une usine des plus modernes, au cœur de l’Europe industrielle, en Alsace sur la commune de Biesheim. Afin de retracer l’histoire de ce site majeur de la filière de l’aluminium, l’Institut pour l’histoire de l’aluminium a lancé au début des années 2000 une campagne de collecte de la mémoire orale auprès des femmes et des hommes qui participèrent par leur travail en production à cette aventure industrielle. Deux de ces entretiens sont présentés dans cet article. Ils témoignent des débuts de la ligne de laminage à chaud - équipement central de ce site - et relatent l’évolution des métiers, de l’organisation du travail. Ainsi retranscrits et réunis dans un corpus sur les activités de transformation de l’aluminium, ils fournissent un précieux matériau pour retracer l’histoire d’une activité, dans ses aspects économiques, techniques et sociaux.

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42

Proulx, Marc-Urbain, Diane Brassard y Mathieu Bouchard-Tremblay. "Structuration au Québec de l’industrie mondiale de l’aluminium en mouvement". Cahiers d'histoire de l'aluminium 68, n.º 1 (13 de julio de 2023): 6–25. http://dx.doi.org/10.3917/cha.068.0006.

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Ce texte offre une analyse de l’industrie de l’aluminium présente au Québec, notamment dans la « Vallée de l’aluminium ». D’abord, les changements structurels récents vécus au sein de cette industrie mondialisée en très forte croissance tendancielle sont esquissés. La filière industrielle québécoise investit diverses activités, dans l’énergie hydroélectrique, la production d’aluminium primaire, la R&D, la fabrication de produits finis, la fourniture de services spécialisés, la conception d’équipements. Le segment problématique de la filiation est celui de la transformation du métal, qui rencontre une barrière à la maturation industrielle. L’analyse de la Vallée de l’aluminium démontre que le régionalisme industriel a généré des outils de soutien endogènes à l’accélération des activités, toutefois sans réussir à lever la barrière, malgré le meilleur avantage énergétique mondial fournit aux alumineries.

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43

Zhang, Yihong, Yong Wu, Puyu Zhou, Zhiyuan Song, Yayun Jia, Weiyi Ouyang, Rafael Luque y Yang Sun. "Effects of Using Aluminum Sulfate as an Accelerator and Acrylic Acid, Aluminum Fluoride, or Alkanolamine as a Regulator in Early Cement Setting". Materials 16, n.º 4 (15 de febrero de 2023): 1620. http://dx.doi.org/10.3390/ma16041620.

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Aluminum sulfate was employed as the main accelerator in order to explore new non-chloride and alkali-free cement accelerators. Acrylic acid, aluminum fluoride, or alkanolamine were used as regulators to further accelerate cement setting. The setting time, compressive, and flexural strengths in cement early strength progress were detected, and both the cement (raw material) and hydrated mortar were fully characterized. The cement setting experiments revealed that only loading acrylic acid as the regulator would decrease the setting time of cement and increase the compressive and flexural strengths of mortar, but further introduction of aluminum fluoride or alkanolamine improved this process drastically. In the meantime, structural characterizations indicated that the raw material (cement) used in this work was composed of C3S (alite), while hydrated mortar consisted of quartz and C3A (tricalcium aluminate). During this transformation, the coordination polyhedron of Al3+ was changed from a tetrahedron to octahedron. This work puts forward a significant strategy for promoting the activity of aluminum sulfate in cement setting and would contribute to the future design of new non-chloride and alkali-free cement accelerators.

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44

Wang, Yuli, Jie Yu, Junjie Wang y Xuemao Guan. "Effects of Aluminum Sulfate and Quicklime/Fluorgypsum Ratio on the Properties of Calcium Sulfoaluminate (CSA) Cement-Based Double Liquid Grouting Materials". Materials 12, n.º 8 (14 de abril de 2019): 1222. http://dx.doi.org/10.3390/ma12081222.

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Grouting materials are used frequently in grouting reinforcement projects, such as mining and coastal engineering. Double liquid grouting materials are mostly used because of the fast setting and high early strength properties when the two slurries are mixed together but high fluidity when the two slurries are separated. In our study, double liquid grouting materials were developed from CSA cement (slurry A), quicklime and fluorgypsum (slurry B). Aluminum sulfate was added in slurry B in order to counteract any adverse effects caused by the fluorgypsum, such as the decreased early compressive strength and the prolonged setting time. The effects of aluminum sulfate content and the quicklime/fluorgypsum ratio on the setting time, hydration heat, and compressive strength of the double liquid grouting materials were investigated, and the hydration products were characterized through thermogravimetry-differential thermal analysis (TG-DTA), X-ray Diffraction (XRD), and Scanning Electron Microscope (SEM) tests. The results show that the addition of aluminum sulfate can shorten the setting time and increase compressive strength at both early and later ages. Considering the setting time and compressive strength of double liquid grouting material at the same time, the optimum content of aluminum sulfate was found to be 2%, and the optimum ratio of quicklime/fluorgypsum was found to be 2:8. The values of the optimum content of aluminum sulfate and ratio of quicklime/fluorgypsum were verified from theoretical analysis.

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45

Song, Zhiyuan, Zainab Bibi, Sidra Chaudhary, Qinxiang Jia, Xiaoyong Li y Yang Sun. "Al(SO4)(OH)·5H2O Stemming from Complexation of Aluminum Sulfate with Water-Soluble Ternary Copolymer and further Stabilized by Silica Gel as Effective Admixtures for Enhanced Mortar Cementing". Materials 17, n.º 19 (27 de septiembre de 2024): 4762. http://dx.doi.org/10.3390/ma17194762.

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A water-soluble ternary copolymer bearing carboxyl, sulfonic, and amide functional groups was synthesized using ammonium persulfate-catalyzed free radical polymerization in water, resulting in high monomer conversion. This copolymer was then complexed with aluminum sulfate, forming an admixture containing Al(SO4)(OH)·5H2O, which was subsequently combined with silica gel. Characterization revealed that the synthesized copolymer formed a large, thin membrane that covered both the aluminum compounds and the silica gel blocks. The introduction of this complex admixture, combining the copolymer and aluminum sulfate, not only reduced the setting times of the cement paste but also enhanced the mechanical strengths of the mortar compared to using aluminum sulfate alone. The complex admixture led to the formation of katoite, metajennite, and C3A (tricalcium aluminate) in the mortar, demonstrating significant linking effects, whereas pure aluminum sulfate could not completely transform C3S within 24 h. Further addition of silica gel to the complex admixture further shortened the setting times of the paste, slightly reduced compressive strength, but improved flexural strength compared to the initial complex admixture. The silicon components appeared to fill the micropores and mesopores of the mortar, accelerating cement setting and enhancing flexural strength, while slightly decreasing compressive strength. This study contributed to the development of new cementing accelerators with improved hardening properties.

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46

Freude, D., J. Haase, H. Pfeifer, D. Prager y G. Scheler. "Extra-framework aluminium in thermally treated zeolite CaA". Chemical Physics Letters 114, n.º 2 (febrero de 1985): 143–46. http://dx.doi.org/10.1016/0009-2614(85)85074-0.

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47

Mioche, Philippe. "A history of aluminium in South Africa". Cahiers d'histoire de l'aluminium 62, n.º 1 (2019): 60. http://dx.doi.org/10.3917/cha.062.0060.

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48

Péjaudier, Hervé. "Peignes en aluminium pour poilus. Autour des occurrences du mot « aluminium » dans Ceux de 14 de Maurice Genevoix". Cahiers d'histoire de l'aluminium 50, n.º 1 (2013): 54. http://dx.doi.org/10.3917/cha.050.0054.

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49

Meshcheryakov, Eugene P., Sergey I. Reshetnikov, Mariya P. Sandu, Alexey S. Knyazev y Irina A. Kurzina. "Efficient Adsorbent-Desiccant Based on Aluminium Oxide". Applied Sciences 11, n.º 6 (10 de marzo de 2021): 2457. http://dx.doi.org/10.3390/app11062457.

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The review describes the main methods of obtaining hydroxides and aluminium oxides (AO) of various structures from gibbsite. The promising techniques of obtaining AO adsorbents are discussed, namely the technique of thermal activation in the mode of pneumatic transport with gibbsite by heated air (TCA Gb) and the technique of thermal activation of gibbsite in centrifugal flash reactors (CTA Gb). The main methods of improving the adsorbent properties of AO, such as the optimisation of texture characteristics and phase composition, as well as the influence of the modification of aluminium oxide adsorbents, obtained using CTA and TCA technologies with cations of alkaline metals, are considered. It is shown that the modification allows a controlled variation of the characteristics of donor and acceptor active sites on the surface of adsorbents and, thus, a substantial increase in their adsorption activity, in particular, with respect to water vapour.

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50

ADEOTI, Guy Oyeniran, Ernesto Cabral HOUEHANOU, Huihuan MA, Eric Adechina ALAMOU y Feng FAN. "Review on Aluminum and Steel Semi-rigid Connections Behavior Design Model". Civil Engineering and Architecture 9, n.º 1 (enero de 2021): 184–205. http://dx.doi.org/10.13189/cea.2021.090116.

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