bluuebunny/crossref_metadata_2025 huggingface dataset:
AI's Theoretical DNA: A Theory of Computation-Inspired Review
Authors: Chaurasia Shubham , Dwivedi Shyam Shankar , Jain Dr. Shubha
Published: September 2024

The burgeoning field of Artificial Intelligence (AI) is deeply intertwined with the principles of the Theory of Computation (ToC), offering a rich landscape for algorithmic exploration and theoretical inquiry. This research article delves into the intricate relationship between algorithms and AI from a ToC perspective, aiming to uncover fundamental insights that underpin the development and understanding of intelligent systems. Commencing with a foundational overview of ToC principles, including automata theory, computability, and complexity theory, the paper elucidates how these concepts serve as the bedrock for modelling and analysing AI algorithms. Through a comprehensive survey it investigates diverse algorithmic paradigms within AI, encompassing machine learning, optimization, and decision-making. Moreover, the article examines how ToC provides a formal framework for characterizing the computational resources and constraints underlying AI algorithms, thereby shedding light on their theoretical capabilities and limitations.
Ulasan Teologis dari Kalimat “Bumi Belum Berbentuk dan Kosong, Gelap Gulita Menutupi Samudera Raya” dalam Kejadian 1:1-2
Authors: Heppy Agustina Harefa  , Yaudi Santos Santoso
Published: September 2024

This journal discusses the meaning and implications of Genesis 1:1-2 in the context of the creation narrative. The main focus is on the primitive condition of the earth before God’s act of creation. Analysis was carried out on the biblical text and various theologians. The findings show that Genesis 1:1-2 describes an unstructured and empety initial state, which later became the foundation for the creation process. The creation narrative in Genesis 1:1-2 is one of the main foundations of Cristian theology. This research aims to dig deeper into the theological meaning of the phrase “the earth was formless and empty” in Genesis 1:1-2. The main focus is on the primitive condition of the earth before creation, and its implications for understanding God’s power and creativity. This research seeks to clarify various existing interpretations, especially regarding the concept of “tohu wabohu” and its relationship with other creation theories. A close analysis of Genesis 1:1-2 shows that the phrase “the earth was formless and empty” describes an intial state that was unstructured and without form. This condition is not the result of previous destruction, but is a “blank canvas” for God’s creative work. Thorugh His words, God transforms chaos into order, brings light into darkness, and creates everything from nothing. This research provides new contributions, namely: presenting a comprehensive review of various theological views regarding Genesis 1:1-2 including comparisons with other creation theories such as the gap theory, providing a deeper interpretation of the concept of “tohu wabohu” and clarifyng misunderstandings that often occur, highlights the implications of understanding the early conditions of the earth for our understanding of God’s power and creativity and the relationship between creator and creation.
II. Péter brazil császár szerepe a Brazíliába irányuló szíriai-libanoni bevándorlásban
Authors: Zámbori Márk Jonatán
Published: September 2024

After the abolition of the institution of slavery in 1888 and the boom in coffee cultivation, a labor shortage emerged in Brazil. The problem was to be solved by the organized resettlement of foreign, primarily European workers. Immigrants willing to work on the coffee plantations were provided with various subsidies by the state. Although only those immigrants engaged in agricultural work on the plantations received government support, this did not mean that the state prohibited spontaneous immigration. Spontaneous immigrants were those who did not arrive in Brazil through recruitment or agency activity and did not receive government support. Such were the Syrian–Lebanese workers who were mainly engaged in commercial rather than agricultural activities. From the second half of the nineteenth century, they left the Ottoman Empire in increasing numbers to try their luck in the Latin American country. The aim of this paper is to prove, relying on primary sources and the results of secondary literature, that even though Syrian-Lebanese immigration to Brazil was spontaneous, Pedro II of Brazil had an important role in encouraging it.
Adapting to Disruption: How Traditional Licensed Accommodations Are Embracing Airbnb through Collaborative Competition
Authors: Matthews Maria , Pantelidis Ioannis S. , Lucena Rodrigo
Published: September 2024

This paper examines how licensed accommodations respond to Airbnb disruption. It focuses on the emerging strategy of ‘collaborative competition,’ where licensed accommodations use Airbnb’s platform as a distribution channel, blending collaboration, with competition. The study highlights a significant shift in business strategy in response to Airbnb's disruption, illustrating initial resistance and retaliation to strategic engagement. This study contributes to the broader understanding of the impact of Airbnb on licensed accommodations and highlights the importance of agility, innovation, and strategic collaboration in the face of disruption, offering valuable insights for both academics and practitioners in the field of hospitality management.
Study on the public awareness of stroke risk factors, symptoms, treatment and rehabilitation: A community based cross sectional survey from a tertiary referral centre in South India
Authors: Balasundaram Padmakumar , Rajan Paul Titus , Libu Gnanaseelan Kanakamma , Philipose Monet , Jassim Mohammed , Yasir Muhammad
Published: September 2024

Background: The incidence of Non communicable diseases (NCDs) including stroke is increasing in India over the past few years. Thrombolysis therapy has revolutionized management of acute ischemic stroke. In spite of such recent advances in stroke therapy, the public remains uninformed about stroke symptoms and management. Objective: To assess the public awareness of stroke risk factors, symptoms, treatment and rehabilitation measures. Methods: The study was a community-based cross-sectional study, designed as an online survey. The tool used for the survey was a semi-structured online questionnaire. Results: Regarding the risk factors of stroke, of the participants, 41 (14.8%) were aware of valvular heart diseases, 18 (6.5%) of lack of exercise, 238 (85.9%) of dyslipedemia, 236 (85.2%) of hypertension, 222 (80.1%) of smoking, and 154 (55.6%) of diabetes. Regarding symptoms of stroke, of the participants, 209 (75.5%) were aware of loss of balance, 240 (86.6%) of speech abnormalities, 261 (94.2%) of facial weakness, and 234 (84.5%) of weakness. Conclusion: Efforts should be made to educate the public regarding uncommon symptoms of stroke, thrombolysis treatment and rehabilitation measures, so that people make beneficial health care decisions in stroke management.
Oral Health Surveillance System in India: Need and Proposal
Authors: Chauhan Neha , Paul Sarah , Bhadauria Upendra Singh , Purohit Bharathi M , Duggal Ritu , Priya Harsh
Published: September 2024

Public health surveillance is described as the ongoing systematic collection, analyzing, and interpreting of the data, closely integrated with the transmission of these data to public health practitioners, doctors, and policymakers responsible to prevent and manage disease as well as injury. Both developed and developing nations are becoming aware of the significance of information from efficient surveillance systems for allocating resources and evaluating programs. Over the past few decades, there was a significant change in oral health profiles around the world. Indicators of oral health have improved in many countries, but not in India. An organized system for providing, monitoring, and evaluating oral health care services is needed in India. Draft National oral health policy 2021 has mentioned specific objectives: (a) by 2025, establish baseline data on the burden of oral diseases in the nation, (b) by 2030, the mortality and morbidity from dental and oro-facial diseases reduce to 15%, (c) By 2025, community-based awareness initiatives and practices for oral health will be covered by the healthcare system by a factor of 50%, and by 2030, by a factor of 70%, (d) the creation of an electronic database at district-level on components of the health system by 2025. A well-defined oral health surveillance system in India will serve the purposes (a) to provide standardized recording procedures, standards, and techniques to collect, analyze and interpret the oral health data at the state and central levels (b) to prioritize oral diseases or conditions that will be the focus of oral health surveillance or disease elimination, (c) to digitally monitor and evaluate the progress of nation’s oral health care programs.
ManuScript Rejection sYndrome (MiSeRY): An Author’s Nightmare
Authors: Bhattacharya Kaushik , Ranjan Priya
Published: September 2024

With majority of the medical journals having a rejection rate of more than 80% of submitted manuscripts, it does come as a shock and grief to the author who had a lot of expectations before submission. Though most of the literature available does mention how to overcome the lacunae in the manuscript before considering resubmission in another journal, none addresses the mental agony and setback the author faces and the way to overcome this setback. Every author should develop immunity and be adequately mentally prepared to overcome this misery. A question- answer session between an eager enthusiastic author, a highly experienced reviewer, and the final authority Editor is presented for guidance.
Analysis of Factors Influencing the Realization of Cultural and Creative Ecosystems in Historical Cities of Iran
Authors: Akbarpour Ganjeh Atieh , Behzadfar Mostafa , Mofidi Shemirani Majid , Khalili Ahmad
Published: September 2024

With the emergence of the concept of the creative city, a new way of thinking about the reciprocal relationship between culture and place has been introduced. This concept, by emphasizing the creative human capital within the city, supports the liberation of individual talents to address urban issues. In this paradigmatic approach, unique indigenous cultural and creative industries are recognized as the primary competitive advantage of cities to achieve economic development. Considering the significant potential of historical cities in Iran to implement the creative city model, the mechanism for establishing a cultural and creative ecosystem in these cities requires investigation. Therefore, the aim of the present study is to evaluate the impact of the spatial preferences of the creative class on the realization of a cultural and creative ecosystem in historical cities of Iran. In the first phase of this research, by reviewing the theoretical foundations in credible global literature, the spatial preferences of the creative class are identified, and the factors influencing the cycle of cultural and creative ecosystems are examined. In the second phase of the research, to test the hypothesis, the structural equation model is utilized within the framework of Amos23 and Spss20 statistical software. This research is applied in nature and descriptive-correlational in terms of data collection and analysis methods. The statistical sample includes 196 members of the creative class residing in the cities of Yazd, Kashan, and Jiroft, who were selected through convenience sampling. The findings indicate that the set of spatial preferences of the creative class affects the implementation of the cultural and creative ecosystem in the historical cities of Iran. If historical cities in Iran seek to implement the creative city model, they must identify the factors that retain and attract the creative class according to their indigenous capacities and, by applying a set of hard and soft creative placemaking factors, provide the possibility of realizing a cultural and creative ecosystem to achieve creative economic development.
Telerehabilitace zaměřená na trénink rovnováhy Kazuistika pacientky s RS
Authors: Grosserová Barbora , Novotná Klára
Published: September 2024

Rehabilitace může být pro řadu pacientů s roztroušenou sklerózou omezeně dostupná, především pro osoby s vyšší mírou neurologické disability. Stále častěji lze pozorovat využívání vzdálených forem rehabilitace prostřednictvím moderních technologií pro zpřístupnění a zkvalitnění dlouhodobé péče potřebným pacientům, které se rozšířily zejména v období pandemických restrikcí. U pacientů s roztroušenou sklerózou vznikla již řada studií, které ukazují, že by telerehabilitace mohla být vhodnou alternativou k běžné rehabilitaci (fyzioterapii). Forem fyzioterapeutických intervencí, které je možné poskytovat na dálku je mnoho, od cvičení prostřednictvím videokonference s fyzioterapeutem, využití specifických zařízení s herními systémy, online aplikací s cvičením nebo cvičení dle předtočených videí.
Předložená práce prezentuje formou kazuistiky zkušenosti našeho pracoviště s dlouhodobou telerehabilitační intervencí, která je zaměřená na trénink rovnováhy.
Problematika mikroinstability v oblasti koxy u profesionálnych tanečníkov klasického baletu
Authors: STREČANSKÁ Andrea , MAŠÁN Ján
Published: September 2024

Východisko: V bedrovom kĺbe existuje široké spektrum pohyblivosti, ktoré môžeme definovať v rozmedzí od zníženého rozsahu pohybu v ktorejkoľvek z rovín SFTR, cez štandardné rozsahy pohybu,  laxitu (asymptomatická hypermobilita)  až po instabilitu (symptomatická hypermobilita). Mikroinstabilita bedrového kĺbu sa často týka malých, subtilných porúch v stabilite kĺbnych štruktúr.
Súbor: Sledovanú kohortu predstavuje 68 profesionálnych tanečníkov klasického baletu Slovenského národného divadla, ktorí splnili predom dané kritéria výberu.
Metódy: Prezentovaná je klinická štúdia v ktorej bolo u profesionálnych tanečníkov klasického baletu Slovenského národného divadla, využité klinické testovanie prostredníctvom testov HEER, AB-HEER a Prone instability test s cieľom identifikovať prítomnosť mikroinstability bedrového kĺbu, posúdenie vplyvu pohlavia  a dominancie strany tela tanečníka na prítomnosť tejto diagnózy.
Výsledky: Testovaním sa potvrdila prítomnosť mikroinstability bedrového kĺbu s veľmi vysokou incidenciu na úrovni 76,9 %. Podrobnejšie analýzy odhalili, že mikroinstabilita sa výraznejšie prejavovala u ženského pohlavia, pričom rozdiel medzi mužmi a ženami bol potvrdený (ženy 90,6 % vs. muži 63,6 %, p<0,01). Rozdiel v strane, na ktorej bola mikroinstabilita zistená nebol medzi pohlaviami štatisticky výrazný. Rovnako nebol zistený rozdiel v prítomnosti mikroinstability a strane jej lokalizácie v skupinách s rozdielnou dominantnou stranou tanečníka. Tieto zistenia okrem vysokej incidencie mikroinstability poukazujú na významné rozdiely medzi pohlavím.
Závery: Prevalencia zranení v oblasti bedrového kĺbu a slabín je u baletných tanečníkov vysoká. Tieto zranenia môžu mať za následok dlhodobú práceneschopnosť, zníženie kvality života a v niektorých prípadoch aj predčasné ukončenie kariéry. Mikroinstabilita je predzvesťou možného závažného poškodenia bedrového kĺbu, preto by tejto problematike u profesionálnych tanečníkov klasického baletu mala byť venovaná dostatočná pozornosť.  Taktiež je nesmierne dôležitá, realizácia výskumov zameraný konkrétne na túto špecifickú skupinu profesionálov. Všeobecným cieľom je dosiahnutie rýchlejšej a efektívnejšej rehabilitácie, čím by bola možná minimalizácia negatívnych  dopadov na kariéru tanečníkov. V testovanej skupine tanečníkov bol pozitívny výsledok na prítomnosť mikroinstability zistený na základe pozitívneho výsledku všetkých troch testov na úrovni 76,9 %, čo nasvedčuje o vysokej prevalencii výskytu. Vyšší výskyt bol zaznamenaný v skupine žien, pričom u nich prevažovala mikroinstabilita na pravom bedrovom kĺbe, avšak bez signifikácie. Zistený bol vzťah medzi pohlavím a výsledkom testu Prone instability a rovnako aj prítomnosťou mikroinstability, vzťah medzi dominantnou stranou tanečníka a mikroinstabilitou na jednotlivých stranách nebol potvrdený.
Slag-steel reactions in the refining of advanced high-strength steel
Authors:   Carnegie Mellon University, Su P , Pistorius P C ,   Carnegie Mellon University, Webler B A ,   Carnegie Mellon University
Published: September 2024

Advanced high-strength steels (AHSS) typically have much higher aluminium concentrations (by an order of magnitude or more) than conventional low-carbon aluminium-killed steels. The resulting lower oxygen activity at the steel-slag interface changes the kinetics and thermodynamics of steel-slag reactions. Previous work showed that the rapid transformation of alumina inclusions to spinel inclusions, and spinel to periclase, occurs because of the relatively high concentration of dissolved magnesium. In this paper, experimental results on nitrogen removal by ladle slag are compared with predictions based on the available thermodynamic databases. As in previous work, the kinetics was modelled by assuming mass transfer control, with steel or slag mass transfer limiting. The results show that significant removal of nitrogen by steel-slag reaction is possible.
Activities of components in Ca2SiO4-Ca3P2O8 solid solution at 1573 K
Authors:   Kyoto University, Saito K , Hasegawa M ,   Kyoto University
Published: September 2024

In steelmaking processes, it is known that P2O5 in dephosphorisation slags often exists in solid solutions between Ca2SiO4 and Ca3P2O8, SS, and thus the solid solutions play an important role in the dephosphorisation reaction. Hence, the knowledge of thermochemical properties, ie phase relations and activities of components, in slags containing SS are necessary for the effective removal of phosphorus from hot metal. In this study, the P2O5 activities in SS were measured through the gas equilibrium method. In the present experiment, oxide samples were equilibrated with Cu-P liquid alloys at 1573 K under a stream of Ar + H2 + H2O or Ar + H2 + CO2 gas mixture in which oxygen potential was fixed and then equilibrium phosphorus concentrations in the Cu-P alloys, [mass%P]Cu, were analysed with ICP-OES. The underlying reaction can be expressed by: 2[P]Cu + (5/2)O2(gas) = P2O5 in oxide K = aP2O5 (pO2/atm)-5/2 [mass%P]Cu-2 Where: K denotes the equilibrium constant aP2O5 represents the P2O5 activity pO2 is the oxygen partial pressure in the gas phase Firstly, the experiments were performed on MgO + Mg3P2O8, in which the P2O5 activity has already been reported, to determine the value for the equilibrium constant, K. Subsequently, the P2O5 activities were measured in SS + CaSiO3 and SS + CaO with the same experimental procedure. The P2O5 activity in SS coexisting with CaO was found to be about seven digits lower than that with CaSiO3 even at the same composition of SS. This phenomenon was explained in terms of the activities of Ca2SiO4 and Ca1.5PO4 (= (1/2)Ca3P2O8). These activities are determined depending on temperature and the composition of SS, while the P2O5 activity depends not only on these variables but also on the second phase coexisting with SS. The Ca2SiO4 and Ca1.5PO4 activities exhibited large negative deviations from Raoult’s law, which implied the strong chemical affinity between the components. Experimental errors in these experiments would be cancelled out in calculating aP2O5 since they would be involved in both experimental procedures for MgO + Mg3P2O8 and SS + CaO or SS + CaSiO3, which makes the present results more reliable.
Pyrometallurgical process simulations using CALPHAD thermodynamic databases
Authors:   Seoul National University, Van Ende M-A , Kumar N ,   Seoul National University, Jung I-H ,   Seoul National University
Published: September 2024

In order to utilise the powerful thermodynamic databases for process simulations, a concept called Effective Equilibrium Reaction Zone (EERZ) was introduced to couple thermodynamic database calculations and reaction kinetics. Using the EERZ concept, many process simulation models for steelmaking processes have been developed within the FactSage steelmaking consortium. After validation of the simulation results by comparing with plant data, the simulation models have been applied to improve plant operations. Several success stories of the improvement of real steelmaking operations are shared. A new user-friendly FactProSim software developed for building process simulations is introduced.
Combined molecular dynamics – experimental investigation of oxidic slag properties
Authors:   Gent University, Bellemans I , Maslov A ,   KU Leuven, Seveno D ,   KU Leuven, Verbeken K ,   Gent University
Published: September 2024

Recycling and decarbonisation current metallurgical processes is key for our planet’s future and in both cases, digital twinning will play an important role. However, the various modelling techniques being used for digital twinning require a lot of input values on variables such as viscosities, diffusion coefficients and surface energies that need to be known as a function of temperature, atmosphere and composition, but which are not widely available, such as in databases, for molten slag phases. The need for more accurate data on physical slag properties is clear and will be extremely relevant for making more realistic and quantitative simulations. Some of these properties are difficult to determine, which is inherent to the very high pyrometallurgical temperatures. Therefore, this work focuses on some aspects related to determining electrical conductivities, viscosities and surface tensions of slags via a combined experimental-modelling method. Besides experimental work, molecular dynamics (MD) simulations can be used to investigate oxidic slag physical properties. With MD simulations, one can follow the time evolution of a system (consisting of atoms or molecules) by integrating Newton’s equation of motion. The input for an MD simulation mainly consists of a force field as well as initial positions, velocities and mass of each atom. The determination of the transport properties in existing literature of MD simulations in oxidic systems, is typically based on incorrect assumptions. For example, to determine the ionic conductivity, the frequently-used Einstein-Stokes equation fails to take into account all ionic types and neglects correlated motion. Furthermore, the viscosity determination via the Einstein-Stokes formula also assumes independent motion of the different ions. This paper gives a brief overview of the opportunities and challenges related to the use of MD simulations for oxidic slag systems.
Thermodynamic modelling of species distribution in AlCl3:BMIC salts
Authors:   University of Alabama, Nahian M K , Reddy R G ,   University of Alabama
Published: September 2024

The thermodynamic model for species distribution in aluminium chloride (AlCl3) and 1-butyl-3-methylimidazolium chloride (BMIC) system was developed. The experimental thermodynamic data, considering a range of aluminium chloride species, such as AlCl4-, Al2Cl7-, Al3Cl10-, Al4Cl13-, and Al2Cl6 were used in developing the model. When the XAlCl3 was in the range of 0 to 0.50, only anion species Cl- and AlCl4- were existing in the solution. As the XAlCl3 value increased more than 0.50, the available anions were Al2Cl7-, Al3Cl10-, Al4Cl13-, and Al2Cl6. Specifically, the concentration of Al2Cl7- increased in the composition range from 0.50 to 0.67 XAlCl3, after which it decreased. This change in the concentration of Al2Cl7- was due to its reaction with excess AlCl3, leading to the formation of Al3Cl10-. The average cathode current density was determined by the electrochemical experiments varying XAlCl3 from 0.50 to 0.71 in the AlCl3:BMIC solutions. The average cathode current density increased as the XAlCl3 increased from 0.50 to 0.67. However, it decreased when the XAlCl3 > 0.67. This trend can be attributed to the electroactive species Al2Cl7-. The Al2Cl7- promotes the reduction rate at the cathode, resulting in an increase in the average cathode current density.
Electrical conductivity measurement of CaO-Al2O3-CaF2 slags by van der Pauw-Ohta Method
Authors:   Kyushu University, Aya K , Sumita T ,   Kyushu University, Saito N ,   Kyushu University, Nakashima K ,   Kyushu University
Published: September 2024

Electro slag remelting (ESR) is one of the methods used to produce high-cleanliness steel. In the ESR method, the product steel electrode is immersed in flux, and the electrode is melted by the Joule heat of the flux generated by high current. CaF2-based melts are mainly used as fluxes, but the electrical conductivity of CaF2-based melts varies widely among researchers and measurement methods. Therefore, this experiment aims to measure the electrical conductivity of CaF2-based melts based on the van der Pauw-Ohta method, which does not require the cell constant that is a fundamental error factor in electrical conductivity measurement at high temperatures. The measurement temperature was set at 1450–1600°C, and dehydrated Ar flowed through the furnace at 200 mL/min. Electrodes were fabricated by Pt-30mass per cent Rh alloy, and the electrodes were connected to an impedance analyser using a four-terminal probe. The electrodes were immersed in the melt, and the impedance and phase angle were measured by AC frequency sweep (50 Hz to 200 kHz). The electrical conductivity was then calculated by utilising the impedance’s real part values when the impedance’s imaginary component was zero. The electrical conductivity showed a positive temperature dependence. The electrical conductivity of 60(CaO⋅Al2O3)-40CaF2 melt increased with increasing temperature but was found to be roughly one-third of those of the previous studies. In the conductivity measurement of 60(CaO⋅Al2O3)-40CaF2 melt, the AC frequency with a phase angle of 0° was found to be different depending on the temperature and immersion depth. By sweeping the frequency, the impedance at the phase angle of 0° can be obtained, which enables us to measure the electrical conductivity more accurately.
Transient slag behaviour in the Direct Reduced Iron (DRI) and scrap-based Electric Arc Furnace (EAF) process – case study for high and low-grade DRI input
Authors:   Tata Steel, Chatterjee S , Panda S K ,   Tata Steel, Van Ende M A ,   Seoul National University
Published: September 2024

Tata Steel Netherlands (TSN) aims to reduce its CO2 emissions by 35–40 per cent by 2030 and become CO2 neutral by 2045. A first step to reach these targets is via the utilisation of an Electric Arc Furnace (EAF), which will run on a mixture of high proportion of Direct Reduced Iron (DRI) and scrap. For an EAF operation, optimisation of slag chemistry is important to achieve the right mix of basicity (for refining especially dephosphorisation), foaming, volume (rate) and refractory life. Slag composition and rate can vary widely depending on the process variables like charge mix, charge composition, feeding rate, oxygen lancing, external carbon injection/addition, fluxing and refractory erosion/corrosion. Moreover, it is important to note that the slag composition and rate are ‘transient’ parameters and change throughout the heat. This makes all the dependent phenomena and/or outcomes transient as well. To describe all these effects simultaneously and be able to realistically simulate the EAF operations, a validated dynamic process model is important in the absence of real plant data. In this study, a validated dynamic EAF process model based on the concept of Effective Equilibrium Reaction Zone (EERZ) has been utilised to analyse the impact of high DRI industrial scale EAF operations on the transient slag characteristics – including slag volume (rate), composition, phases, solid fraction and viscosity. Simultaneously, the model is able to predict the impact on steel and off-gas characteristics. Case studies were performed with 70 per cent DRI:30 per cent scrap mix considering both low and high-grade DRI. Both melting and refining aspects of the process including continuous feeding, arcing program, carbon addition, fluxing and oxy-lancing were considered.
Development of solid waste-based flux and its application in out-of-furnace dephosphorisation of low-silicon hot metal
Authors:   University of Science and Technology Beijing, Zhao Z , Zhang Y ,   University of Science and Technology Beijing
Published: September 2024

The green production of the steelmaking process has urgent requirements for fluorine-free fluxes. In this article, a new solid waste-based slagging flux was applied in the external dephosphorisation test of low silicon hot metal to replace the traditional fluorite-lime dephosphorisation slag. The results showed that under laboratory conditions, the new flux was utilised for smelting low-silicon molten iron with a phosphorus content of 0.10~0.13 wt per cent, the temperature of the molten iron was 1350°C and the slag amount was controlled at 2 per cent. Within ten minutes of smelting, the dephosphorisation rate of the molten iron reached more than 50 per cent. When making slag with new flux, the slag melting time was about 40 seconds and the P2O5 content in the final slag was higher than 8 wt per cent. In the industrial test of a 150 t molten iron ladle, under the same molten iron conditions, an out-of-furnace dephosphorisation test was conducted in the Kambara Reactor (KR) process. The flux material consumption per ton of steel was 8~10 kg. Within 15 minutes of smelting, the dephosphorisation rate of the molten iron was about 30 per cent. During flux slag making, the slag melting time was about three minutes and the P2O5 content in the final slag was higher than 6 wt per cent. This new solid waste-based flux has significant cost advantages and out-of-furnace dephosphorisation effects and is expected to become the benchmark for a new generation of fluorine-free steelmaking fluxes.
Modelling of liquid/liquid interface movement during spindle rotation of refractory – slag corrosion test
Authors:   Tech University of Korea, Lee H , Choi B ,   Hyundai Steel, Chung Y ,   Tech University of Korea
Published: September 2024

Numerous studies have explored refractory corrosion in the presence of slag and/or metal, utilising the Finger Rotating Test (FRT). Recent experimental results revealed that corrosion initially increased with rising rotation velocity but was then suppressed above a critical rotating speed, under conditions involving a two-liquid solution of slag and molten steel. This phenomenon indicated that the liquid/liquid interface movement occurred during spindle rotor. However, understanding of the phenomenon, known as the rod climbing effect, remains inadequate in the case involving slag, molten steel and refractories. To gain deeper insights, a simulation experiment was conducted on the phenomenon using silicon oil/water and the phenomenon was analysed using computerised simulation software (Ansys Fluent). Experimental modelling demonstrated that interfacial movement occurs even at low rotation velocity, as low as 200 rev/min, when the viscosity of silicone oil is at 100 cP. Computational analysis utilising the Volume of Fluid (VOF) method and a realisable k-ε turbulence model elucidated that interface elevation during rotor rotation arises due to viscosity disparities between the two fluids. Furthermore, this movement is more pronounced when the viscosity difference is lower. Additionally, the study findings suggest that higher density differences between two liquids suppress the phenomenon of interface movement.
Towards integration of pyro- and hydrometallurgical unit operations for efficient recovery of battery metals from waste lithium-ion batteries
Authors:   Aalto University, Klemettinen L , Biswas J ,   IIT Bombay, Klemettinen A ,   Aalto University, Zhang J ,   Wuhan University of Science and Technology, O’Brien H ,   Geological Survey of Finland, Partinen J ,   Aalto University, Jokilaakso A ,   Aalto University
Published: September 2024

Waste lithium-ion batteries (LIBs) are important secondary sources of many valuable materials, including Critical Raw Materials (CRMs) defined by the European Union (EU): lithium, cobalt, manganese, and graphite. Additionally, LIBs typically contain nickel and copper, which are classified as Strategic Raw Materials for EU since 2023. In recent years, great effort has been made to develop efficient recycling processes for waste LIBs. Pyrometallurgical processes have been essential in industrial production of metals for many decades. These technologies are relatively mature, with high adaptability for different raw materials. Pyrometallurgical treatment in LIB recycling typically involves the use of smelting processes, in which waste batteries are heated above their melting points and metals are separated through a reduction reaction in the liquid phase. Through this recycling route, cobalt, copper, and nickel can be efficiently recovered in the form of a metal alloy, whereas lithium and manganese are lost in the slag phase. The goal of this work was to increase the recoveries of valuable battery metals through a combination of hydro- and pyrometallurgical unit operations. First, industrial Li-ion battery scrap underwent a selective sulfation roasting stage, where the aim was to transform LiCoO2 and Mn-oxides into Li, Co and Mn sulfates. After roasting, the battery scrap was leached in distilled water with a solid to liquid ratio of 100 g/L at 60°C and recovered 95 per cent of Li, 61 per cent of Mn and 35 per cent of Co. After leaching, the solid leach residue was mixed with industrial Ni-slag and biochar, followed by reduction at 1350°C in argon atmosphere. The high-temperature smelting experiments were conducted as a function of time (5–60 mins) to investigate the reduction behaviour of battery metals. The results show that Co and Ni from the slag and leach residue can be efficiently recovered in the slag cleaning stage.
Analysis of the melting behaviour of CaF2-free welding fluxes using hot thermocouple technique
Authors:   Indian Institute of Technology Bombay, Gowravaram S L A , Basu S ,   Indian Institute of Technology Bombay
Published: September 2024

CaF2 has been a common constituent in a wide variety of welding fluxes, including those used for submerged arc welding (SAW). The widespread use of CaF2 stems from its role in lowering the liquidus temperature as well as the viscosity of the molten slag that covers the weld pool. However, the harmful effect of fluoride evaporation from molten flux, on the environment as well as the health of the users is becoming increasingly evident over the years. This has led to increasing attention towards reducing the CaF2 concentration in the fluxes. The fluoride-free formulations face the challenging requirement to maintain the thermo-physical properties (viscosity, liquidus temperature etc) like those observed in fluoride-containing fluxes. In the present work, three fluxes with compositions in the CaO-MnO-SiO2-Al2O3 system have been identified as promising alternatives to the CaF2-rich fluxes. However, the thermo-physical properties of any such flux need to be comparable to CaF2-based commercial SAW fluxes before it can be adopted for regular use. The single hot thermocouple technique (SHTT) has been used by several researchers in the past as a tool for observing the melting and solidification characteristics of fluxes. This device has been developed in the present work and is used to characterise the melting behaviour of the fluxes. The measured solidus and liquidus temperatures from SHTT were compared with the results from differential thermal analysis (DTA) and simulations using the FactSage™ software for a comprehensive understanding. In spite of having a slight deviation in the measured values from the multiple techniques, the results obtained from these multiple methods show that the selected compositions could be potential CaF2 free alternative welding fluxes.
Relationship between thermal conductivity and structure of alkaline earth (Ca, Mg) aluminoborosilicate melts
Authors:   University of Tokyo, Yamada S , Aoki H ,   JFE Steel Corporation, Nakayama A ,   Nippon Steel Corporation, Morita K ,   University of Tokyo
Published: September 2024

The thermal conductivity of mold flux is crucial for optimising the productivity and quality of steels. This study investigates the thermal conductivity of molten oxides, including CaO-BO1.5-AlO1.5 (CBA), CaO-BO1.5-AlO1.5-SiO2 (CBAS), and CaO-MgO-BO1.5-AlO1.5 (CMBA) melts, using a hot wire method. Additionally, their structure is examined using Raman spectrometry and magic angle spinning nuclear magnetic resonance (MAS-NMR) to explore their relationship. Furthermore, first-principles calculations are employed to assess the covalency of each bond in the melts for a more quantitative analysis of their relationship. The study confirms that an increase in the CaO concentration of the CaO-BO1.5-AlO1.5 melts reduces the amount of bridging oxygen and consequently decreases thermal conductivity. The covalency of the B[4]-O bond is highest, especially when the second-nearest-neighbour Al atoms transition from Al[6] to Al[4], forming the AlB3O7 structure with B[4]. The relationship between thermal conductivity and the structure of CaO-BO1.5-AlO1.5-SiO2 melts can be quantitatively assessed using the degree of polymerisation of the network structure and the variation of covalency as indicators. Furthermore, replacing CaO with MgO in the CaO-MgO-BO1.5-AlO1.5 melts reveals a mixed alkaline earth effect on thermal conductivity.
The effect of FeO/SiO2 ratio on the feasibility of utilising iron silicate slags as supplementary cementitious materials
Authors:   Luleå University of Technology, Andersson A , Isaksson J ,   Luleå University of Technology, Brander L ,   Research Institutes of Sweden, Lennartsson A ,   Luleå University of Technology, Roos Å ,   Boliden Smelters, Engström F ,   Luleå University of Technology
Published: September 2024

Slags are the most voluminous solid by-products generated in pyrometallurgical operations, and, as such, finding an application for these oxidic materials is pertinent to maintaining resource efficiency. In particular, pyrometallurgical copper production is associated with high slag rates, typically ranging from 2.2 to 3.0 tons of slag per ton produced copper, which necessitates slag valourisation. A possible application for these iron silicate slags is as supplementary cementitious materials (SCMs), which effectively lowers the CO2 emissions per ton of cementitious material. Although utilising iron silicate slags as SCMs has been studied in previous work, the scientific literature has limited data on the effect of composition on the inherent reactivity in cementitious systems. More specifically, no reports on the impact of FeO/SiO2 ratio have been presented in previous publications. Therefore, the present study aimed to isolate this parameter in a synthetic FeO-SiO2-Al2O3-CaO-MgO-Cr2O3 system. Since the amorphous content is a pertinent parameter for SCMs, a high-temperature confocal laser scanning microscope (HT-CLSM) was utilised to assess the crystallisation behaviour at continuous cooling conditions. Furthermore, high-temperature rheological experiments were conducted to measure the viscosities of the slags in relation to the crystallisation behaviour. The experiments showed that depolymerising the slag by increasing the FeO/SiO2 ratio generated a less viscous slag, which showed higher tendencies for crystallisation. Furthermore, experiments assessing the inherent reactivity as an SCM showed that depolymerising the slag by increasing the FeO/SiO2 ratio as the sole independent parameter generated an initially more reactive slag. However, replacing SiO2 with FeO was found to negatively affect the reactivity as measured over seven days within the tested compositional range.
The MOLTEN Conference series and research trends in slags, fluxes and salts 1980–2023
Authors:   University of Queensland, Hayes P , Jak E ,   University of Queensland
Published: September 2024

Molten slags, fluxes and salts play key roles in a wide range of the high temperature industrial process applications, including metals production, refining and recycling, metal manufacturing processes, electrochemical metal production cells, batteries, and efficient heat transfer media. Recognising the importance and significance of fundamental scientific knowledge of these systems, the International MOLTEN Conference series was established to provide a forum to bring together leading academic researchers and industrial engineers to present and discuss the latest scientific ideas and findings, and their application in their respective fields. This article presents an analysis of the research carried out in this field over time in terms of the number of journal articles, fields and slag systems studied and geographical origin of the research.
Solubility of nitrogen and inclusion characteristics in high aluminium steels
Authors:   Indian Institute of Technology Bombay, Ishfaq M , Pande M M ,   Indian Institute of Technology Bombay
Published: September 2024

The effect of aluminium on nitrogen solubility was investigated by equilibrating melt comprising master alloy of Fe-Al with pure electrolytic iron in a controlled atmosphere (pure argon) at 1873 K. Nitrogen in the samples was measured by sampling technique using inert gas fusion absorptiometry. It was found that nitrogen content decreases steadily with aluminium concentration and gradually, becomes close to 1 ppm for very high aluminium steels. Wagner’s second order interaction parameter formalism has been used to estimate the equilibrium constant and interaction parameters. Scanning electron microscopy (SEM) investigation showed, dual-phase inclusions comprising AlN phase surrounding alumina core. The 3D morphology of inclusions was studied by extracting the sample from the top and the central bottom portion of the solidified ingot. A sparse distribution of nitrogen was found for most of the inclusions which manifested the presence of almost pure alumina inclusions with different morphologies and sizes.
Measuring circular economy through life cycle assessment – challenges and recommendations based on a study on recycling of Al dross, bottom ash and shavings
Authors:   Norwegian University of Science and Technology, Pastor-Vallés E , Vallejo-Olivares A ,   Norwegian University of Science and Technology, Tranell G ,   Norwegian University of Science and Technology, Pettersen J B ,   Norwegian University of Science and Technology
Published: September 2024

Metals are essential for the sustainability transition and decarbonisation of society. Yet, it will be paramount to produce them sustainably and minimise the affiliated resource and energy use and the associated emissions. In the circular economy, the metallurgical industry should recycle existing material stocks, and improve its utilisation of wastes, residues and side streams. This increases the complexity of processes, as they become both (often multi-fraction) waste treatment as well as material production processes and brings complexity to the assessment of environmental benefits. Assessing the environmental impact of technological developments frequently is supported by life cycle assessment (LCA). While the method is well documented, its implementation involves several methodological choices that deserve reasoning and analysis, such as how to define the product when former wastes are turned into new products, the selection of impact methodology when converting emissions to environmental indicators, the definition of system boundaries and co-product allocation and the interpretation of sensitivity and uncertainty in final outcomes. In this exploratory study, we investigate how the variation of LCA set-up affects the environmental burden of the system. We consider a metallurgical process where a mix of hard-to-recycle aluminium-containing streams is used to produce aluminium cast alloys in a rotary furnace. Re-melting with salt-fluxes allows recovering metals from partly oxidised/contaminated streams, such as dross, bottom ash and industrial shavings, but at the expense of generating significant amounts of salt-slag/salt-cake hazardous waste. The study considers different system alternatives such as landfilling the salt-slag residues versus valourising them into salts, aluminium concentrates, ammonium sulfate and non-metallic-compounds to be used by the metallurgical, construction or chemical industries. Practical recommendations are outlined to facilitate the implementation of LCA in assessing the potential benefits of the circular economy in the metallurgical sector.
Effect of oxygen on the interfacial phenomena and metal recovery rate in recycling process
Authors:   POSTECH, Park J , Kang Y-B ,   POSTECH, Park J H ,   Hanyang University
Published: September 2024

In order to understand the effect of oxygen injection into the molten metal on the valuable metals (VM) recovery and interfacial phenomena, several high-temperature experiments were conducted using a high-frequency induction furnace with a quartz tube as the reaction chamber at 1673 K. Copper-based waste printed circuit board (PCB) that contains some impurities was selected as the end-of-life resource. CaO-SiO2 based pre-fused slag and oxygen gas were used in present works. The composition change and microstructure of the samples were analysed. As oxygen was injected into the system, impurities were rapidly removed. After the removal of impurities, continuously injected oxygen lowered interfacial tension between liquid slag and liquid metal. Lowered interfacial tension induced Cu loss into the slag.
Direct observation of the fayalite slag formation behaviour from large SiO2 grains
Authors:   Sumitomo Metal Mining Co., Ltd. & Tohoku University, Goto Y , Kawanishi S ,   Kyoto University, Natsui S ,   Tohoku University, Takahashi J ,   Sumitomo Metal Mining Co., Ltd., Nogami H ,   Tohoku University
Published: September 2024

The demand for copper increases yearly, and further improvements in copper smelting efficiency using flash furnaces are required. This study was conducted to understand and promote the interfacial reaction associated with the collision of silica flux and iron oxide particles, ie the formation reaction of fayalite slag, in the reaction shaft of the flash furnace. High-temperature microscopy was used to observe the reaction behaviour of a 2 mm granular SiO2 reagent in contact with micrometre-order-sized FeO reagents in situ. When the amount of FeO was lower than the stoichiometric amount with SiO2, the molten slag formed at the interface between FeO and SiO2 diffused into the SiO2 particle before dissolving the remaining FeO particles. It did not contribute to the subsequent reaction, and despite having the lowest amount of FeO among the samples in this study, many unreacted FeO particles remained on the surface of the samples after testing. On the other hand, under conditions with high FeO content and close to the eutectic composition of the FeO-SiO2 system, a liquid phase formed from low temperatures, gradually increasing in volume and eventually completely dissolving the 2 mm SiO2 grain. These results indicate that the early-stage slag is essential in increasing the interfacial area between FeO and SiO2 and facilitating the supply of FeO to SiO2. In other words, the FeO/SiO2 determines the amount of liquid phase and significantly influences the subsequent interfacial reaction rate between FeO and SiO2. Therefore, the local FeO/SiO2 of the particles falling down the reaction shaft should also be optimised to ensure early slag formation. Meanwhile, the time required for 2 mm SiO2 to complete the reaction for the temperature history employed in this study was significantly longer than the particle residence time in the reaction shaft. Further detailed investigation of the effects of silica flux particle size, composition, and reaction temperature on the reaction time will help find the conditions under which the reaction of silica flux can be completed in the reaction shaft. These kinetic approaches could contribute to future innovations in the copper smelting process using flash furnaces.