The Mechanism of Joint Reduction of MoO3 and CuO by Combined Mg/C Reducer at High Heating Rates

Understanding of the decisive role of the interaction mechanism and kinetics in the combustion processes is highly relevant for the elaboration of optimal conditions for obtaining Mo-Cu composite powders. From this perspective, the efficient delivery of the reduction mechanism of copper and molybdenum oxides with combined Mg + C reducing agents at high heating rates is crucial to develop a valuable approach for the combustion synthesis of Mo-Cu composite powders. Herein, we shed light on the mechanism of the reactions in all the studied binary, ternary and quaternary systems contemporaneously demonstrating the effect of the heating rate on the conversion degree. The combination of two highly exothermic and speedy reactions (MoO3+3Mg and CuO+Mg vs MoO3+CuO+4Mg) led to a slow interaction with weak self-heating (dysynergistic effect) due to a change in the reaction mechanism. On the other hand, it has been shown that during the simultaneous utilization of the Mg and C reducing agents, the process begins exclusively with carbothermic reduction, and at relatively high temperatures it continues with magnesiothermic one. The effective activation energy values of the magnesiothermic stages of the studied reactions were determined by Kissinger isoconversional method.

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The Mechanism of Joint Reduction of MoO3 and CuO by Combined Mg/C Reducer at High Heating Rates

Journal of Composites Science ◽

10.3390/jcs5120318 ◽

2021 ◽

Vol 5 (12) ◽

pp. 318

Author(s):

Hasmik Kirakosyan ◽

Khachik Nazaretyan ◽

Sofiya Aydinyan ◽

Suren Kharatyan

Keyword(s):

Interaction Mechanism ◽

Decisive Role ◽

Isoconversional Method ◽

Reducing Agents ◽

Isothermal Treatment ◽

Molybdenum Oxides ◽

Heating Rates ◽

High Heating ◽

Combustion Processes

Understanding of the decisive role of non-isothermal treatment on the interaction mechanism and kinetics of the MoO3-CuO-Mg-C system is highly relevant for the elaboration of optimal conditions at obtaining Mo-Cu composite powder in the combustion processes. The reduction pathway of copper and molybdenum oxides with combined Mg + C reducing agents at high heating rates from 100 to 5200 K min−1 was delivered. In particular the sequence of the reactions in all the studied binary, ternary and quaternary systems contemporaneously demonstrating the effect of the heating rate on products’ phase composition and microstructure was elucidated. The combination of two highly exothermic and speedy reactions (MoO3 + 3Mg and CuO + Mg vs. MoO3 + CuO + 4Mg) led to a slow interaction with weak self-heating (dysynergistic effect) due to a change in the reaction mechanism. Furthermore, it has been shown that upon the simultaneous utilization of the Mg and C reducing agents, the process initiates exclusively with carbothermic reduction, and at relatively high temperatures it continues with magnesiothermic reaction. The effective activation energy values of the magnesiothermic stages of the studied reactions were determined by Kissinger isoconversional method.

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Joint Reduction of NiO/WO3 Pair and NiWO4 by Mg + C Combined Reducer at High Heating Rates

Metals ◽

10.3390/met11091351 ◽

2021 ◽

Vol 11 (9) ◽

pp. 1351

Author(s):

Marieta Zakaryan ◽

Khachik Nazaretyan ◽

Sofiya Aydinyan ◽

Suren Kharatyan

Keyword(s):

Composite Materials ◽

High Speed ◽

Synergetic Effect ◽

Isoconversional Method ◽

Heating Rates ◽

Formation Pathway ◽

High Heating ◽

Functional Features ◽

Maximum Temperatures ◽

Solid Liquid

Functional features of Ni-W composite materials combined with successful performance enabled a breakthrough in their broad application. To disclose the formation pathway of Ni-W composite materials at extreme conditions of combustion synthesis in the NiO-WO3-Mg-C and NiWO4-Mg-C systems for the optimization of the synthesis procedure, the process was modeled under programmed linear heating conditions by thermal analysis methods. The reduction kinetics of tungsten and nickel oxides mixture and nickel tungstate by Mg + C combined reducer at non-isothermal conditions was studied at high heating rates (100–1200 °C min−1) by high-speed temperature scanner techniques. It was shown that when moving from low heating to high heating rates, the mechanism of both the magnesiothermic and magnesio-carbothermic reductions of the initial mixtures changes; that is, the transition from a solid-solid scheme to a solid-liquid scheme is observed. The strong influence of the heating rate on the reduction degree and kinetic parameters of the systems under study was affirmed. The simultaneous utilization of magnesium and carbon as reducers allowed the lowering of the starting and maximum temperatures of reduction processes, as evidenced by the synergetic effect at the utilization of a combined reducer. The effective values of activation energy (Ea) for the reactions proceeding in the mixtures NiO + WO3 + 4Mg, NiO + WO3 + 2.5Mg + 1.5C, NiWO4 + 4Mg and NiWO4 + 2Mg + 2C were estimated by Kissinger isoconversional method and were 146 ± 10, 141 ± 10, 216 ± 15 and 148 ± 15 kJ mol−1, respectively.

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Comparing fast inductive tempering and conventional tempering: Effects on microstructure and mechanical properties

Metallurgical Research & Technology ◽

10.1051/metal/2018015 ◽

2018 ◽

Vol 115 (4) ◽

pp. 407 ◽

Cited By ~ 4

Author(s):

Annika Eggbauer Vieweg ◽

Gerald Ressel ◽

Peter Raninger ◽

Petri Prevedel ◽

Stefan Marsoner ◽

...

Keyword(s):

Mechanical Properties ◽

Impact Energy ◽

Charpy Impact ◽

Heat Treating ◽

Processing Route ◽

High Heating Rate ◽

Heating Rates ◽

High Heating ◽

Tempering Treatment ◽

Carbide Distribution

Induction heating processes are of rising interest within the heat treating industry. Using inductive tempering, a lot of production time can be saved compared to a conventional tempering treatment. However, it is not completely understood how fast inductive processes influence the quenched and tempered microstructure and the corresponding mechanical properties. The aim of this work is to highlight differences between inductive and conventional tempering processes and to suggest a possible processing route which results in optimized microstructures, as well as desirable mechanical properties. Therefore, the present work evaluates the influencing factors of high heating rates to tempering temperatures on the microstructure as well as hardness and Charpy impact energy. To this end, after quenching a 50CrMo4 steel three different induction tempering processes are carried out and the resulting properties are subsequently compared to a conventional tempering process. The results indicate that notch impact energy raises with increasing heating rates to tempering when realizing the same hardness of the samples. The positive effect of high heating rate on toughness is traced back to smaller carbide sizes, as well as smaller carbide spacing and more uniform carbide distribution over the sample.

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Modulation of Macrophages M1/M2 Polarization Using Carbohydrate-Functionalized Polymeric Nanoparticles

Polymers ◽

10.3390/polym13010088 ◽

2020 ◽

Vol 13 (1) ◽

pp. 88

Author(s):

Raquel G. D. Andrade ◽

Bruno Reis ◽

Benjamin Costas ◽

Sofia A. Costa Lima ◽

Salette Reis

Keyword(s):

Inflammatory Responses ◽

Polymeric Nanoparticles ◽

Interaction Mechanism ◽

Mannose Receptor ◽

The Body ◽

Receptor Expression ◽

Production Methods ◽

Polymeric Nanocarriers ◽

Efficient Delivery

Exploiting surface endocytosis receptors using carbohydrate-conjugated nanocarriers brings outstanding approaches to an efficient delivery towards a specific target. Macrophages are cells of innate immunity found throughout the body. Plasticity of macrophages is evidenced by alterations in phenotypic polarization in response to stimuli, and is associated with changes in effector molecules, receptor expression, and cytokine profile. M1-polarized macrophages are involved in pro-inflammatory responses while M2 macrophages are capable of anti-inflammatory response and tissue repair. Modulation of macrophages’ activation state is an effective approach for several disease therapies, mediated by carbohydrate-coated nanocarriers. In this review, polymeric nanocarriers targeting macrophages are described in terms of production methods and conjugation strategies, highlighting the role of mannose receptor in the polarization of macrophages, and targeting approaches for infectious diseases, cancer immunotherapy, and prevention. Translation of this nanomedicine approach still requires further elucidation of the interaction mechanism between nanocarriers and macrophages towards clinical applications.

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Effect of low and high heating rates on reaction path of Ni(V)/Al multilayer

Materials Chemistry and Physics ◽

10.1016/j.matchemphys.2017.02.033 ◽

2017 ◽

Vol 193 ◽

pp. 244-252 ◽

Cited By ~ 9

Author(s):

Łukasz Maj ◽

Jerzy Morgiel ◽

Maciej Szlezynger ◽

Piotr Bała ◽

Grzegorz Cios

Keyword(s):

Reaction Path ◽

Heating Rates ◽

High Heating

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A FUNDAMENTAL STUDY ON THE COMBUSTION CHARACTERISTICS OF MUNICIPAL WASTE PLASTICS UNDER HIGH HEATING RATES

10.12681/eadd/5411 ◽

1995 ◽

Author(s):

Θωμαή Παναγιώτου

Keyword(s):

Combustion Characteristics ◽

Municipal Waste ◽

Waste Plastics ◽

Heating Rates ◽

Fundamental Study ◽

High Heating

ΑΥΤΗ Η ΕΡΓΑΣΙΑ ΕΙΝΑΙ ΜΙΑ ΒΑΣΙΚΗ ΕΡΕΥΝΑ ΕΠΑΝΩ ΣΤΗΝ ΚΑΥΣΗ ΠΛΑΣΤΙΚΩΝ ΠΟΥ ΒΡΙΣΚΟΝΤΑΙ ΣΤΑ ΑΠΟΡΡΙΜΑΤΑ (ΠΟΛΥ-ΣΤΥΡΕΝΙΟ (PS), ΠΟΛΥ-ΕΘΥΛΕΝΙΟ (ΡΕ) ΚΑΙ PVC). ΣΦΑΙΡΙΚΑ ΣΩΜΑΤΙΔΙΑ ΠΛΑΣΤΙΚΩΝ ΙΣΟΥ ΜΕΓΕΘΟΥΣ ΔΗΜΙΟΥΡΓΗΘΗΚΑΝ ΣΤΟ ΕΡΓΑΣΤΗΡΙΟ ΚΑΙ ΚΑΗΚΑΝ ΕΝΑ, ΕΝΑ ΣΕ ΗΛΕΚΤΡΙΚΟ ΦΟΥΡΝΟ ΚΑΙ ΘΕΡΜΟΚΡΑΣΙΕΣ 1040 -1400 Κ. Η ΚΑΥΣΗ ΤΩΝ ΣΩΜΑΤΙΔΙΩΝ ΜΕΛΕΤΗΘΗΚΕ ΜΕ ΕΝΑ ΤΡΙΧΡΩΜΑΤΙΚΟ ΠΥΡΟΜΕΤΡΟ ΚΑΙ ΜΙΑ ΥΨΗΛΗΣ ΤΑΧΗΤΗΤΑΣ ΚΙΝΗΜΑΤΟΓΡΑΦΙΚΗ ΜΗΧΑΝΗ, ΩΣΤΕ ΝΑ ΣΥΛΛΕΧΘΟΥΝ ΟΙ ΕΞΗΣ ΠΛΗΡΟΦΟΡΙΕΣ: Α) Ο ΧΡΟΝΟΣ ΤΗΣ ΚΑΥΣΗΣ, Β) ΤΟ ΕΙΔΟΣ ΤΗΣ ΚΑΥΣΗΣ (ΟΜΟΙΟΓΕΝΗΣ Η ΕΤΕΡΟΓΕΝΗΣ), Γ) ΤΟ ΠΑΧΟΣ ΤΗΣ ΦΛΟΓΑΣ ΚΑΙ Δ) Η ΤΑΧΥΤΗΤΑ ΠΤΩΣΗΣ ΤΩΝ ΣΩΜΑΤΙΔΙΩΝ. ΟΙ ΠΛΗΡΟΦΟΡΙΕΣ ΑΥΤΕΣ ΧΡΗΣΙΜΟΠΟΙΗΘΗΚΑΝ ΓΙΑ ΤΟΝ ΥΠΟΛΟΓΙΣΜΟ ΤΗΣ ΣΤΙΓΜΙΑΙΑΣ ΠΕΡΙΕΚΤΙΚΟΤΗΤΑΣ ΤΗΣ ΦΛΟΓΑΣ ΣΕ ΑΙΘΑΛΗ ΚΑΙ ΤΗΣ ΠΡΩΤΕΥΟΥΣΑΣ ΦΥΣΙΚΗΣ ΚΑΙ ΧΗΜΙΚΗΣ ΔΙΕΡΓΑΣΙΑΣ ΚΑΤΑ ΤΗΝ ΚΑΥΣΗ ΤΩΝ ΣΩΜΑΤΙΔΙΩΝ. ΚΑΘΕ ΥΛΙΚΟ ΠΑΡΟΥΣΙΑΣΕ ΜΟΝΑΔΙΚΑ ΧΑΡΑΚΤΗΡΙΣΤΙΚΑ ΚΑΥΣΗΣ. ΟΙ ΦΛΟΓΕΣ ΤΩΝ PVC ΣΩΜΑΤΙΔΙΩΝ ΕΙΧΑΝ ΤΗΝ ΜΕΓΑΛΥΤΕΡΗ ΠΕΡΙΕΚΤΙΚΟΤΗΤΑ ΣΕ ΑΙΘΑΛΗ, ΕΝΩ ΤΩΝ ΡΕ ΤΗΝ ΜΙΚΡΟΤΕΡΗ. Η ΤΑΧΥΤΗΤΑ ΚΑΥΣΗΣ ΤΩΝ PS ΣΩΜΑΤΙΔΙΩΝ ΒΡΕΘΗΚΕ ΟΤΙ ΕΞΑΡΤΑΤΑΙ ΑΠΟ ΤΗΝ ΤΑΧΥΤΗΤΑ ΔΙΑΧΥΣΗΣ ΣΤΗΝ ΑΕΡΙΑ ΦΑΣΗ, ΕΝΩ ΤΩΝ ΡΕ ΑΠΟ ΤΗΝ ΤΑΧΥΤΗΤΑ ΠΥΡΟΛΥΣΗΣ ΤΩΝ ΣΩΜΑΤΙΔΙΩΝ. Η ΑΝΑΦΛΕΞΗ ΤΩΝ PVC ΣΩΜΑΤΙΔΙΩΝ ΕΜΠΟΔΙΣΤΗΚΕ ΑΠΟ ΤΗΝ ΥΠΑΡΞΗ ΤΗΣ ΧΛΩΡΙΝΗΣ ΠΟΥ ΔΙΕΦΥΓΕ ΑΡΧΙΚΑ. ΟΤΑΝ Η ΚΑΥΣΗ ΑΡΧΙΣΕ, ΔΗΜΙΟΥΡΓΗΘΗΚΕ ΜΙΑ ΠΑΧΙΑ ΚΑΙ ΠΡΟΑΝΑΜΙΓΜΕΝΗ ΦΛΟΓΑ ΓΥΡΩΑΠΟ ΤΟ ΣΩΜΑΤΙΔΙΟ.

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PTFE–Al2O3 reactive interaction at high heating rates

Journal of Thermal Analysis and Calorimetry ◽

10.1007/s10973-014-4080-0 ◽

2014 ◽

Vol 119 (1) ◽

pp. 245-251 ◽

Cited By ~ 23

Author(s):

M. A. Hobosyan ◽

Kh. G. Kirakosyan ◽

S. L. Kharatyan ◽

K. S. Martirosyan

Keyword(s):

Heating Rates ◽

High Heating ◽

Reactive Interaction

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Pyrolysis and Hydropyrolysis of Peat at High Heating Rates

Fundamentals of Thermochemical Biomass Conversion ◽

10.1007/978-94-009-4932-4_17 ◽

1985 ◽

pp. 315-327 ◽

Cited By ~ 3

Author(s):

H. Eklund ◽

W. Wanzl

Keyword(s):

Heating Rates ◽

High Heating

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Evolution of Gases from the Pyrolysis of Raw and Torrefied Biomass and from the Oxy-combustion of their Bio-Chars

Journal of Energy Resources Technology ◽

10.1115/1.4051146 ◽

2021 ◽

pp. 1-30

Author(s):

Xiaoxiao Meng ◽

Wei Zhou ◽

Emad Rokni ◽

Xigang Yang ◽

Yiannis Levendis

Keyword(s):

Co2 Emissions ◽

Carbon Capture ◽

Heating Rates ◽

Renewable Biomass ◽

Carbon Capture And Utilization ◽

Combustion Emissions ◽

Torrefied Biomass ◽

High Heating ◽

Pyrolysis Of Biomass ◽

N Compounds

Abstract The current research assessed the evolution of gases from pyrolysis of biomass and from subsequent combustion of bio-chars. Raw and torrefied biomass was pyrolyzed in nitrogen or carbon dioxide under high heating rates (104 K/s) and high temperatures (1450 K). Pyrolyzates gases were monitored for carbon, nitrogen and sulfur oxides. Subsequently, generated bio-chars were burned in both conventional (air) and simulated oxy-combustion (O2/CO2) gases. In principle, oxy-combustion of renewable biomass coupled with carbon capture and utilization/sequestration can help remove atmospheric CO2. Pyrolysis of biomass in CO2 generated lower char yields, lower SO2 and NO, and higher CO2, CO and HCN mole fractions, compared to pyrolysis in N2. HCN was the most prominent among all measured nitrogen-bearing gases (HCN, NH3, NO) from biomass pyrolysis. Compared to their combustion in air, bio-chars burned more effectively in 30%O2/79%CO2 and less effectively in 21%O2/79%CO2. Emissions of CO were the lowest in 21%O2/79%CO2. Emissions of HCN were the highest in air combustion, and decreased with increasing O2 mole fraction in oxy-combustion; emissions of NO were highest in 30%O2/79%CO2, and emissions of NO were dominant during bio-char oxy-combustion compared with other N-compounds. In oxy-combustion bio-chars released the lowest emissions of SO2. Finally, the emissions of CO, NO, HCN, and SO2 from combustion of DDGS bio-chars were higher than those from RH bio-chars, because of different physicochemical properties.

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