Modeling of Thermo-Chemo-Mechanical Properties of Anode Mixture during the Baking Process

In the Hall–Héroult process, prebaked carbon anodes are utilized to produce primary aluminium. The quality of the anode plays a crucial role in the efficiency of electrowinning primary aluminium. In the production of anodes, the anode baking is considered as the stage most frequently causing anode problems. During the baking process, the anode undergoes complex physicochemical transformations. Moreover, the anode at a lower position, imposed by loading pressures from upper anodes, will creep during this process. Thus, the production of high-quality anodes demands efficient control of their baking process. This paper aims to investigate the thermo-chemo-mechanical properties of the anode paste mixture at high temperatures. These properties include kinetic parameters of pitch pyrolysis such as the activation energy and the pre-exponential factor, the thermal expansion coefficient (TEC) and relevant mechanical parameters related to the elastic, the viscoelastic and the viscoplastic behaviours of the anode. For this purpose, experiments consisting of the thermogravimetric analysis, the dilatometry and the creep test were carried out. Based on the obtained results, the forementioned parameters were identified. Relevant mechanical parameters were expressed as a function of a new variable, called the shrinking index, which is related to the volatile released in open and closed pores of the anode. This variable would be used to highlight the chemo-mechanical coupling effect of the anode mixture. New insights into the phenomena such as the expansion due to the increase of the pore pressure and the chemical shrinkage of the anode during the baking process were also gained in this work. These investigations pave the way for modeling the thermo-chemo-poromechanical behaviour of the anode during the baking process.

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Numerical Simulation of Cutting Stress Deformation in Tungsten Carbide Turning Tools

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.836.203 ◽

2016 ◽

Vol 836 ◽

pp. 203-207

Author(s):

Pei Hsing Huang ◽

Jian Rong Chen ◽

Hong Zhong Lu

Keyword(s):

Thermal Deformation ◽

Coupling Effect ◽

Cutting Speed ◽

Mechanical Coupling ◽

Machining Errors ◽

Steady State Temperature ◽

Steel Analysis ◽

Aisi 1045 ◽

Tool Cutting

With the aim of enhancing the precision and quality of turning processes, this study investigated cutting stress and thermal deformation induced by friction between the tool and chip of a Wolfram carbide (WC) tool cutting AISI-1045 carbon steel. Analysis of cutting stress and thermal deformation using COMSOL Multiphysics software is useful for evaluating the compensation for machining errors and reducing tool wear. Three cutting loads were adopted for the simulation of the thermal conduction, and changes in temperature and the stress field. Simulation results show that thermal deformation in the tool tip is proportional to cutting speed and time. As long as the temperature of the tool remains below the quasi-steady-state temperature, the amount of deformation does not change significantly. An understanding of the thermo-mechanical coupling effect during turning can help to improve the accuracy of compensation for thermal deformation in turning tools.

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Effect of Sand Wetting on Physically Hardened Moulding Sands Containing a Selected Inorganic Binder. Part 1

Archives of Foundry Engineering ◽

10.1515/afe-2016-0006 ◽

2016 ◽

Vol 16 (1) ◽

pp. 73-78

Author(s):

M. Stachowicz ◽

K. Granat ◽

Ł. Pałyga

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Water Glass ◽

Mechanical Parameters ◽

Significant Positive Effect ◽

Technological Parameters ◽

Physical Methods ◽

High Silica ◽

Positive Effect

Abstract In the paper, an attempt was made to evaluate the effect of preliminary wetting of high-silica base during preparation of moulding sands containing a selected grade of sodium water-glass, designed for hardening by traditional drying or by electromagnetic microwaves at 2.45 GHz. In the research, some water was dosed during stirring the sandmix before adding 1.5 wt% of the binder that was unmodified sodium water-glass grade 137, characterised by high molar module within 3.2 to 3.4. Scope of the examinations included determining the effect of wetting the base on mechanical parameters like compression, bending and tensile strength, as well as on technological parameters like permeability, abrasion resistance and apparent density. The research revealed a significant positive effect of adding water to wet surfaces of high-silica base grains on mechanical properties and quality of moulding sands hardened by physical methods, in particular by microwave heating.

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Thermal–Mechanical Processing and Strengthen in AlxCoCrFeNi High-Entropy Alloys

Frontiers in Materials ◽

10.3389/fmats.2020.585602 ◽

2021 ◽

Vol 7 ◽

Author(s):

Jinshan Li ◽

Haoxue Yang ◽

William Yi Wang ◽

Hongchao Kou ◽

Jun Wang

Keyword(s):

Mechanical Properties ◽

Phase Transition ◽

Coupling Effect ◽

Engineering Application ◽

Engineering Properties ◽

High Entropy Alloys ◽

Secondary Phases ◽

Mechanical Coupling ◽

High Entropy ◽

Transition Mechanism

In this study high-entropy alloys (HEAs) were devised based on a new alloy design concept, which breaks with traditional design methods for conventional alloys. As a novel alloy, HEAs have demonstrated excellent engineering properties and possible combinations of diverse properties for their unique tunable microstructures and properties. This review article explains the phase transition mechanism and mechanical properties of high-entropy alloys under the thermal-mechanical coupling effect, which is conducive to deepening the role of deformation combines annealing on the structure control and performance improvement of high-entropy alloys, giving HEAs a series of outstanding performance and engineering application prospect. To reach this goal we have explored the microstructural evolution, formation of secondary phases at high and/or intermediate temperatures and their effect on the mechanical properties of the well known AlxCoCrFeNi HEAs system, which not only has an important role in deepening the understanding of phase transition mechanism in AlxCoCrFeNi HEAs, but also has important engineering application value for promoting the application of high-entropy alloys.

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Physical Property Evolution of the Anode Mixture during the Baking Process

Materials ◽

10.3390/ma14040923 ◽

2021 ◽

Vol 14 (4) ◽

pp. 923

Author(s):

Bowen Chen ◽

Hicham Chaouki ◽

Donald Picard ◽

Julien Lauzon-Gauthier ◽

Houshang Alamdari ◽

...

Keyword(s):

High Temperatures ◽

Coal Tar ◽

Physical Property ◽

Apparent Volume ◽

Air Permeability ◽

Coal Tar Pitch ◽

Baking Process ◽

Aluminium Production ◽

Efficient Control ◽

Carbon Anodes

The Hall-Héroult process uses prebaked carbon anodes as electrodes. The anode’s quality plays a crucial role in the efficiency of the aluminium production process. During the baking process, the anode undergoes complex physicochemical transformations. Thus, the production of high-quality anodes depends, among others, on the efficient control of their baking process. This paper aims to investigate the evolution of some physical properties of the anode paste mixture during the baking process. These properties include the mass loss fraction, real and apparent densities, the ratio of apparent volume, the permeability, and porosities. For this purpose, experiments consisting of thermogravimetric analysis, dilatometry, air permeability, and helium-pycnometric measurements were carried out. The anode permeability at high temperatures was linked to the air permeability through a permeability correlator due to experimental limitations. Moreover, the real density at high temperatures was estimated by combining real densities of the coal tar pitch and coke aggregates. Different porosities, such as the open porosity and the closed porosity related to the pitch binder, were estimated by taking the permeability at high temperatures into account. In this context, the effect of the permeability correlator, which was introduced to link the permeability at high temperatures to the air permeability, was investigated through a sensitivity analysis. These results allow an estimation of the shrinking index, a new variable introduced to reflect the baking level of the anode mixture, which is linked to the volatile that is released in both open and closed pores. Afterwards, the pore pressure inside closed pores in the coal tar pitch was estimated. The obtained results highlight some new insights related to the baking process of the anode mixture. Moreover, they pave the way for better modeling of the thermo-chemo-mechanical behavior of anodes at high temperatures.

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Pengaruh Tekanan dan Penggunaan Conplast terhadap Sifat Mekanik Eternit dari Abu Cangkang Sawit

Jurnal Riset Teknologi Industri ◽

10.26578/jrti.v8i15.1552 ◽

2016 ◽

Vol 8 (15) ◽

pp. 47-54

Author(s):

Haspiadi Haspiadi

Keyword(s):

Mechanical Properties ◽

Oil Palm ◽

Modulus Of Elasticity ◽

Modulus Of Rupture ◽

Palm Shell ◽

Oil Palm Shell ◽

Density Values ◽

Test Result

The purpose of this research is to know the influence of pressure and use of conplast against mechanical properties which are a Modulus of Elasticity (MOE) and Modulus of Rupture (MOR) of plasterboard. The study is done because still low quality of plasterboard made from a mixture of ashes of oil-palm shell especially of the mechanical properties compared to the controls. The method of this reserach used variation of printed pressure and the addition of conplast. Test result is obtained that the highest value of Modulus of Elasticity (MOE) 90875.94 Kg/cm2, Modulus of Rupture (MOR) 61.16 Kg/cm2 and density values in generally good printed at the pressure 60 g/cm3 and the addition of conplast 25% as well as the composition of the ash of palm shell oil 40%: limestone 40%: cement 15%: fiber 5% and 300 mL of water. ABSTRAK Tujuan dari penelitian ini adalah untuk mengetahui pengaruh tekanan dan penggunaan conplast terhadap sifat mekanik yaitu kuat lentur dan keteguhan patah eternit berbahan dasar abu cangkang sawit. Penelitian ini dilakukan karena masi rendahnya mutu eternit berbahan campuran abu cangkang sawit dari bolier khususnya sifat mekanik dibandingkan dengan kontrol. Metode penelitian yang digunakan adalah dengan variasi tekanan cetak dan penambahan conplast. Hasil uji diperoleh bahwa kuat lentur tertinggi sebesar 90875,94 Kg/cm2 dan keteguhan patah sebesar 61,16 Kg/cm2, yang dicetak pada tekanan 60 g/cm3 dan penambahan conplast 25% dengan komposisi abu cangkang sawit 40 %: kapur 40 % : semen 15 %: serat 5 % dan air 300 mL.Kata Kunci : Abu cangkang sawit, conplast, kuat lentur, keteguhan patah.

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Beam Theory of Thermal–Electro-Mechanical Coupling for Single-Wall Carbon Nanotubes

Nanomaterials ◽

10.3390/nano11040923 ◽

2021 ◽

Vol 11 (4) ◽

pp. 923

Author(s):

Kun Huang ◽

Ji Yao

Keyword(s):

Mechanical Properties ◽

Carbon Nanotubes ◽

Beam Theory ◽

Bending Stiffness ◽

Single Wall Carbon Nanotubes ◽

Beam Model ◽

Euler Beam ◽

New Model ◽

Mechanical Coupling ◽

Electrostatic Fields

The potential application field of single-walled carbon nanotubes (SWCNTs) is immense, due to their remarkable mechanical and electrical properties. However, their mechanical properties under combined physical fields have not attracted researchers’ attention. For the first time, the present paper proposes beam theory to model SWCNTs’ mechanical properties under combined temperature and electrostatic fields. Unlike the classical Bernoulli–Euler beam model, this new model has independent extensional stiffness and bending stiffness. Static bending, buckling, and nonlinear vibrations are investigated through the classical beam model and the new model. The results show that the classical beam model significantly underestimates the influence of temperature and electrostatic fields on the mechanical properties of SWCNTs because the model overestimates the bending stiffness. The results also suggest that it may be necessary to re-examine the accuracy of the classical beam model of SWCNTs.

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Investigation of Color Reproduction on Linen Fabrics when Printing with Mimaki TX400-1800D Inkjet with Pigment TP250 Dyes

Coatings ◽

10.3390/coatings11030354 ◽

2021 ◽

Vol 11 (3) ◽

pp. 354

Author(s):

Tim Tofan ◽

Rimantas Stonkus ◽

Raimondas Jasevičius

Keyword(s):

Mechanical Properties ◽

Color Reproduction ◽

Related Effect ◽

Color Characteristics ◽

Fabric Density ◽

Different Types ◽

The Difference ◽

Printing Parameters ◽

Linen Fabric

The aim of this research is to investigate related effect of dyeability to linen textiles related to different printing parameters. The study investigated the change in color characteristics when printing on linen fabrics with an inkjet MIMAKI Tx400-1800D printer with pigmented TP 250 inks. The dependence of color reproduction on linen fabrics on the number of print head passes, number of ink layers to be coated, linen fabric density, and different types of linen fabric was investigated. All this affects the quality of print and its mechanical properties. The change in color characteristics on different types of linen fabrics was determined experimentally. We determine at which print settings the most accurate color reproduction can be achieved on different linen fabrics. The difference between the highest and the lowest possible number of head passages was investigated. The possibilities of reproducing different linen fabric colors were determined.

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Effect of carbon anode production parameters on anode cracking

SN Applied Sciences ◽

10.1007/s42452-020-04133-8 ◽

2021 ◽

Vol 3 (2) ◽

Author(s):

Salah Amrani ◽

Duygu Kocaefe ◽

Yasar Kocaefe ◽

Dipankar Bhattacharyay ◽

Mohamed Bouazara ◽

...

Keyword(s):

Electrical Resistivity ◽

Crack Density ◽

Raw Material ◽

Carbon Anode ◽

Know How ◽

Production Parameters ◽

Environmental Emissions ◽

Carbon Anodes ◽

Tomographic Analysis

AbstractCarbon anodes are used in the electrolytic production of aluminum. The quality of anodes is directly related to the production cost, carbon and energy consumption, and environmental emissions. It is desired that the anodes have high density, low porosity/cracks, low electrical resistivity as well as low air and CO2 reactivities. Low resistivity of anodes reduces energy required to produce aluminum during electrolysis. The presence of cracks and pores increases the anode electrical resistivity. Therefore, it is important to know how and when the pores and cracks form during the anode production so that the necessary actions could be taken to prevent their formation. A study was carried out to investigate the effect of different anode production parameters such as anode composition, type of raw material used, time and top-former bellow pressure of vibro-compactor, green anode cooling medium, and heating rate used during baking on the crack formation. The anodes are fabricated at the carbon laboratory of University of Quebec at Chicoutimi (UQAC) and characterized by measuring their properties (density, electrical resistivity, and surface crack density). The anode properties, hence the anode quality, were correlated with the anode production parameters. Also, their tomographic analysis was carried out to visualize and quantify the internal cracks. Graphical abstract

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The Influence of Different Plasma Cell Discharges on the Performance Quality of Surgical Gown Samples

Materials ◽

10.3390/ma14154329 ◽

2021 ◽

Vol 14 (15) ◽

pp. 4329

Author(s):

Atif H. Asghar ◽

Ahmed Rida Galaly

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Exposure Time ◽

Electrical Characteristics ◽

Cathode Fall ◽

Treatment Efficiency ◽

Performance Quality ◽

Surgical Gown ◽

The One

An experimental study was performed on a low-density plasma discharge using two different configurations of the plasma cell cathode, namely, the one mesh system electrodes (OMSE) and the one mesh and three system electrodes (OMTSE), to determine the electrical characteristics of the plasma such as current–voltage characteristics, breakdown voltage (VB), Paschen curves, current density (J), cathode fall thickness (dc), and electron density of the treated sample. The influence of the electrical characteristics of the plasma fluid in the cathode fall region for different cathode configuration cells (OMSE and OMTSE) on the performance quality of a surgical gown was studied to determine surface modification, treatment efficiency, exposure time, wettability property, and mechanical properties. Over a very short exposure time, the treatment efficiency for the surgical gown surface of plasma over the mesh cathode at a distance equivalent to the cathode fall distance dc values of the OMTSE and for OMSE reached a maximum. The wettability property decreased from 90 to 40% for OMTSE over a 180 s exposure time and decreased from 90 to 10% for OMSE over a 160 s exposure time. The mechanisms of each stage of surgical gown treatment by plasma are described. In this study, the mechanical properties of the untreated and treated surgical gown samples such as the tensile strength and elongation percentage, ultimate tensile strength, yield strength, strain hardening, resilience, toughness, and fracture (breaking) point were studied. Plasma had a more positive effect on the mechanical properties of the OMSE reactor than those of the OMTSE reactor.

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Evolution of Meniscal Biomechanical Properties with Growth: An Experimental and Numerical Study

Bioengineering ◽

10.3390/bioengineering8050070 ◽

2021 ◽

Vol 8 (5) ◽

pp. 70

Author(s):

Marco Ferroni ◽

Beatrice Belgio ◽

Giuseppe M. Peretti ◽

Alessia Di Giancamillo ◽

Federica Boschetti

Keyword(s):

Mechanical Properties ◽

Stress Relaxation ◽

Developmental Stage ◽

Mechanical Response ◽

Numerical Study ◽

Numerical Models ◽

Mechanical Stimulus ◽

Specific Response ◽

Mechanical Parameters ◽

Biochemical Analyses

The menisci of the knee are complex fibro-cartilaginous tissues that play important roles in load bearing, shock absorption, joint lubrication, and stabilization. The objective of this study was to evaluate the interaction between the different meniscal tissue components (i.e., the solid matrix constituents and the fluid phase) and the mechanical response according to the developmental stage of the tissue. Menisci derived from partially and fully developed pigs were analyzed. We carried out biochemical analyses to quantify glycosaminoglycan (GAG) and DNA content according to the developmental stage. These values were related to tissue mechanical properties that were measured in vitro by performing compression and tension tests on meniscal specimens. Both compression and tension protocols consisted of multi-ramp stress–relaxation tests comprised of increasing strains followed by stress–relaxation to equilibrium. To better understand the mechanical response to different directions of mechanical stimulus and to relate it to the tissue structural composition and development, we performed numerical simulations that implemented different constitutive models (poro-elasticity, viscoelasticity, transversal isotropy, or combinations of the above) using the commercial software COMSOL Multiphysics. The numerical models also allowed us to determine several mechanical parameters that cannot be directly measured by experimental tests. The results of our investigation showed that the meniscus is a non-linear, anisotropic, non-homogeneous material: mechanical parameters increase with strain, depend on the direction of load, and vary among regions (anterior, central, and posterior). Preliminary numerical results showed the predominant role of the different tissue components depending on the mechanical stimulus. The outcomes of biochemical analyses related to mechanical properties confirmed the findings of the numerical models, suggesting a specific response of meniscal cells to the regional mechanical stimuli in the knee joint. During maturation, the increase in compressive moduli could be explained by cell differentiation from fibroblasts to metabolically active chondrocytes, as indicated by the found increase in GAG/DNA ratio. The changes of tensile mechanical response during development could be related to collagen II accumulation during growth. This study provides new information on the changes of tissue structural components during maturation and the relationship between tissue composition and mechanical response.

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