Pub Date : 2024-11-14DOI: 10.1016/j.apt.2024.104723
So Segawa , Prima Asmara Sejati , Yosephus Ardean Kurnianto Prayitno , Noritaka Saito , Masahiro Takei
<div><div>Spatiotemporal distribution visualization of solid volume fraction during LiCl-KCl molten salt solidification has been visualized by thermal-compensated electrical resistance tomography (<em>tc</em>ERT). The <em>tc</em>ERT consists of three steps which are 1) conductivity interpolation step, 2) conventional conductivity reconstruction step, and 3) phase-fraction conversion step. In the first step, the liquid electrical conductivity <span><math><mrow><msup><mrow><mspace></mspace></mrow><mi>L</mi></msup><mi>σ</mi><mrow><mo>(</mo><mi>x</mi><mo>,</mo><mi>T</mi><mo>)</mo></mrow></mrow></math></span> under mole fraction <span><math><mrow><mi>x</mi></mrow></math></span> of KCl and measured temperature <span><math><mrow><mi>T</mi></mrow></math></span> is defined by conductivity interpolation diagram (CID). In the second step, the electrical conductivity during solidification is defined by the conventional heat-resistant ERT as the reconstructed solid and liquid conductivity <span><math><mrow><msup><mrow><mspace></mspace></mrow><mrow><mi>S</mi><mo>+</mo><mi>L</mi></mrow></msup><mrow><mi>σ</mi><mo>(</mo><mi>r</mi><mo>,</mo><mi>θ</mi><mo>,</mo><mi>T</mi><mrow><mo>(</mo><mi>t</mi><mo>)</mo></mrow></mrow></mrow></math></span>. From both steps, the solidification volume fraction <span><math><mrow><mi>φ</mi><mo>(</mo><mi>r</mi><mo>,</mo><mi>θ</mi><mo>,</mo><mi>T</mi><mo>(</mo><mi>t</mi><mo>)</mo><mo>)</mo></mrow></math></span> is calculated by the solid–liquid conductivity model (SLCM) which converts <span><math><mrow><msup><mrow><mspace></mspace></mrow><mrow><mi>S</mi><mo>+</mo><mi>L</mi></mrow></msup><mi>σ</mi><mrow><mo>(</mo><mi>r</mi><mo>,</mo><mi>θ</mi><mo>,</mo><mi>T</mi><mrow><mo>(</mo><mi>t</mi><mo>)</mo></mrow><mo>)</mo></mrow></mrow></math></span> into <span><math><mrow><mi>φ</mi><mo>(</mo><mi>r</mi><mo>,</mo><mi>θ</mi><mo>,</mo><mi>T</mi><mo>(</mo><mi>t</mi><mo>)</mo><mo>)</mo></mrow></math></span> by referring to <span><math><mrow><msup><mrow><mspace></mspace></mrow><mi>L</mi></msup><mi>σ</mi><mrow><mo>(</mo><mi>x</mi><mo>,</mo><mi>T</mi><mo>)</mo></mrow></mrow></math></span>. The <em>tc</em>ERT was applied to a composition of 85 mol % LiCl–15 mol % KCl in a crucible with platinum-wire electrodes under the initial temperature <span><math><mrow><msup><mrow><mspace></mspace></mrow><mn>0</mn></msup><mi>T</mi><mo>=</mo></mrow></math></span> 700 °C and at cooling rate <span><math><mrow><mi>γ</mi><mo>=</mo></mrow></math></span> 4.44 °C/min. As the results, inhomogeneous and unsteady <span><math><mrow><mi>φ</mi><mo>(</mo><mi>r</mi><mo>,</mo><mi>θ</mi><mo>,</mo><mi>T</mi><mo>(</mo><mi>t</mi><mo>)</mo><mo>)</mo></mrow></math></span> distributions were precisely visualized with a maximum relative error <span><math><mrow><mi>ζ</mi><mo>=</mo></mrow></math></span> 0.763 of space-mean <span><math><mrow><mo>〈</mo><mi>φ</mi><mo>〉</mo><mo>(</mo><mi>T</mi><mo>(</mo><mi>t</mi><mo>)</mo><mo>)</mo></mrow></math></span>, where the inhomogeneity refers to the sp
{"title":"Spatiotemporal distribution visualization of solid volume fraction during LiCl-KCl molten salt solidification by thermal-compensated electrical resistance tomography (tcERT)","authors":"So Segawa , Prima Asmara Sejati , Yosephus Ardean Kurnianto Prayitno , Noritaka Saito , Masahiro Takei","doi":"10.1016/j.apt.2024.104723","DOIUrl":"10.1016/j.apt.2024.104723","url":null,"abstract":"<div><div>Spatiotemporal distribution visualization of solid volume fraction during LiCl-KCl molten salt solidification has been visualized by thermal-compensated electrical resistance tomography (<em>tc</em>ERT). The <em>tc</em>ERT consists of three steps which are 1) conductivity interpolation step, 2) conventional conductivity reconstruction step, and 3) phase-fraction conversion step. In the first step, the liquid electrical conductivity <span><math><mrow><msup><mrow><mspace></mspace></mrow><mi>L</mi></msup><mi>σ</mi><mrow><mo>(</mo><mi>x</mi><mo>,</mo><mi>T</mi><mo>)</mo></mrow></mrow></math></span> under mole fraction <span><math><mrow><mi>x</mi></mrow></math></span> of KCl and measured temperature <span><math><mrow><mi>T</mi></mrow></math></span> is defined by conductivity interpolation diagram (CID). In the second step, the electrical conductivity during solidification is defined by the conventional heat-resistant ERT as the reconstructed solid and liquid conductivity <span><math><mrow><msup><mrow><mspace></mspace></mrow><mrow><mi>S</mi><mo>+</mo><mi>L</mi></mrow></msup><mrow><mi>σ</mi><mo>(</mo><mi>r</mi><mo>,</mo><mi>θ</mi><mo>,</mo><mi>T</mi><mrow><mo>(</mo><mi>t</mi><mo>)</mo></mrow></mrow></mrow></math></span>. From both steps, the solidification volume fraction <span><math><mrow><mi>φ</mi><mo>(</mo><mi>r</mi><mo>,</mo><mi>θ</mi><mo>,</mo><mi>T</mi><mo>(</mo><mi>t</mi><mo>)</mo><mo>)</mo></mrow></math></span> is calculated by the solid–liquid conductivity model (SLCM) which converts <span><math><mrow><msup><mrow><mspace></mspace></mrow><mrow><mi>S</mi><mo>+</mo><mi>L</mi></mrow></msup><mi>σ</mi><mrow><mo>(</mo><mi>r</mi><mo>,</mo><mi>θ</mi><mo>,</mo><mi>T</mi><mrow><mo>(</mo><mi>t</mi><mo>)</mo></mrow><mo>)</mo></mrow></mrow></math></span> into <span><math><mrow><mi>φ</mi><mo>(</mo><mi>r</mi><mo>,</mo><mi>θ</mi><mo>,</mo><mi>T</mi><mo>(</mo><mi>t</mi><mo>)</mo><mo>)</mo></mrow></math></span> by referring to <span><math><mrow><msup><mrow><mspace></mspace></mrow><mi>L</mi></msup><mi>σ</mi><mrow><mo>(</mo><mi>x</mi><mo>,</mo><mi>T</mi><mo>)</mo></mrow></mrow></math></span>. The <em>tc</em>ERT was applied to a composition of 85 mol % LiCl–15 mol % KCl in a crucible with platinum-wire electrodes under the initial temperature <span><math><mrow><msup><mrow><mspace></mspace></mrow><mn>0</mn></msup><mi>T</mi><mo>=</mo></mrow></math></span> 700 °C and at cooling rate <span><math><mrow><mi>γ</mi><mo>=</mo></mrow></math></span> 4.44 °C/min. As the results, inhomogeneous and unsteady <span><math><mrow><mi>φ</mi><mo>(</mo><mi>r</mi><mo>,</mo><mi>θ</mi><mo>,</mo><mi>T</mi><mo>(</mo><mi>t</mi><mo>)</mo><mo>)</mo></mrow></math></span> distributions were precisely visualized with a maximum relative error <span><math><mrow><mi>ζ</mi><mo>=</mo></mrow></math></span> 0.763 of space-mean <span><math><mrow><mo>〈</mo><mi>φ</mi><mo>〉</mo><mo>(</mo><mi>T</mi><mo>(</mo><mi>t</mi><mo>)</mo><mo>)</mo></mrow></math></span>, where the inhomogeneity refers to the sp","PeriodicalId":7232,"journal":{"name":"Advanced Powder Technology","volume":"35 12","pages":"Article 104723"},"PeriodicalIF":4.2,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142656257","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-09DOI: 10.1016/j.apt.2024.104714
Md. Obaidullah , Newaz Mohammed Bahadur , Md. Abdullah Al Nahid , Iqbal Ahmed Siddiquey , Takeshi Furusawa , Masahide Sato , Noboru Suzuki
Core-shell nanocomposites (NCs) of Fe2O3@TiO2 were synthesized using a microwave assisted sol–gel method in a relatively short time. These NCs were characterized using several techniques, including Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM), diffuse reflectance spectroscopy (DRS), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The TEM images showed the formation of a ∼ 4.2 nm TiO2 layer around the spherical Fe2O3 core particles. The presence of Ti 2p peaks in both the wide and narrow scan XPS spectra, along with the distinct diffraction peak in the XRD patterns, confirmed the successful synthesis of Fe2O3@TiO2 NCs. Vibration sample magnetometer (VSM) analysis showed that the NCs exhibited sufficient magnetization for catalyst separation after photocatalytic tests. The photocatalytic performance of the Fe2O3@TiO2 NCs was compared with that of uncoated Fe2O3 nanoparticles for methylene blue degradation under visible light.
{"title":"Microwave assisted sol gel synthesis of Fe2O3@TiO2 core–shell nanocomposite for the enhanced photocatalytic activity under visible light and the investigation of their optical properties","authors":"Md. Obaidullah , Newaz Mohammed Bahadur , Md. Abdullah Al Nahid , Iqbal Ahmed Siddiquey , Takeshi Furusawa , Masahide Sato , Noboru Suzuki","doi":"10.1016/j.apt.2024.104714","DOIUrl":"10.1016/j.apt.2024.104714","url":null,"abstract":"<div><div>Core-shell nanocomposites (NCs) of Fe<sub>2</sub>O<sub>3</sub>@TiO<sub>2</sub> were synthesized using a microwave assisted sol–gel method in a relatively short time. These NCs were characterized using several techniques, including Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM), diffuse reflectance spectroscopy (DRS), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The TEM images showed the formation of a ∼ 4.2 nm TiO<sub>2</sub> layer around the spherical Fe<sub>2</sub>O<sub>3</sub> core particles. The presence of Ti 2p peaks in both the wide and narrow scan XPS spectra, along with the distinct diffraction peak in the XRD patterns, confirmed the successful synthesis of Fe<sub>2</sub>O<sub>3</sub>@TiO<sub>2</sub> NCs. Vibration sample magnetometer (VSM) analysis showed that the NCs exhibited sufficient magnetization for catalyst separation after photocatalytic tests. The photocatalytic performance of the Fe<sub>2</sub>O<sub>3</sub>@TiO<sub>2</sub> NCs was compared with that of uncoated Fe<sub>2</sub>O<sub>3</sub> nanoparticles for methylene blue degradation under visible light.</div></div>","PeriodicalId":7232,"journal":{"name":"Advanced Powder Technology","volume":"35 12","pages":"Article 104714"},"PeriodicalIF":4.2,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142656255","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, sulfidation roasting was used to modify the copper ferrite to improve its flotation performance for the first time. The flotation results showed that the recovery of modified copper ferrite reached 91.63 %. The sulfidation mechanisms of copper ferrite at high temperatures were systematically investigated by X-ray diffraction (XRD) combining with thermodynamic calculations, X-ray photoelectron spectroscopy (XPS) and electron probe microanalysis (EPMA). XRD and thermodynamic analyses revealed that the CuFe2O4 was first reduced to compounds of Cu2O and Fe2O3, and was then converted to Cu2S and Fe3O4 with the increase of sulfur dosage at high temperatures. XPS analyses indicated that both the Cu2S and CuSO4 were mainly formed on the surface of mineral after the sulfidation treatment. The EPMA analyses confirmed that Cu2S was generated at the outer layer of samples after the sulfidation, while the inner part of particles was mainly composed of Fe3O4. It is concluded that the sulfidation reaction of CuFe2O4 occurred from the surface to interior during the thermal process. The sulfidation reaction pathway was devised as the follows: CuO·Fe2O3 → CuOx·Fe2O3(0 < x < 1) → Cu2O + Fe2O3 → Cu2S + Fe2O3 → Cu2S + Fe3O4 to better interpret the transformation mechanisms of CuFe2O4. These results will provide a good theoretical basis for the recovery of Cu and Fe from the refractory oxide copper resource by the combined methods of sulfidation and flotation.
{"title":"Sulfidation behavior of copper ferrite induced with sulfur and flotation responses","authors":"Yusong Huang , Yongxing Zheng , Ziqi Guo , Jinfang Lv","doi":"10.1016/j.apt.2024.104715","DOIUrl":"10.1016/j.apt.2024.104715","url":null,"abstract":"<div><div>In this study, sulfidation roasting was used to modify the copper ferrite to improve its flotation performance for the first time. The flotation results showed that the recovery of modified copper ferrite reached 91.63 %. The sulfidation mechanisms of copper ferrite at high temperatures were systematically investigated by X-ray diffraction (XRD) combining with thermodynamic calculations, X-ray photoelectron spectroscopy (XPS) and electron probe microanalysis (EPMA). XRD and thermodynamic analyses revealed that the CuFe<sub>2</sub>O<sub>4</sub> was first reduced to compounds of Cu<sub>2</sub>O and Fe<sub>2</sub>O<sub>3</sub>, and was then converted to Cu<sub>2</sub>S and Fe<sub>3</sub>O<sub>4</sub> with the increase of sulfur dosage at high temperatures. XPS analyses indicated that both the Cu<sub>2</sub>S and CuSO<sub>4</sub> were mainly formed on the surface of mineral after the sulfidation treatment. The EPMA analyses confirmed that Cu<sub>2</sub>S was generated at the outer layer of samples after the sulfidation, while the inner part of particles was mainly composed of Fe<sub>3</sub>O<sub>4</sub>. It is concluded that the sulfidation reaction of CuFe<sub>2</sub>O<sub>4</sub> occurred from the surface to interior during the thermal process. The sulfidation reaction pathway was devised as the follows: CuO·Fe<sub>2</sub>O<sub>3</sub> → CuO<sub>x</sub>·Fe<sub>2</sub>O<sub>3</sub>(0 < x < 1) → Cu<sub>2</sub>O + Fe<sub>2</sub>O<sub>3</sub> → Cu<sub>2</sub>S + Fe<sub>2</sub>O<sub>3</sub> → Cu<sub>2</sub>S + Fe<sub>3</sub>O<sub>4</sub> to better interpret the transformation mechanisms of CuFe<sub>2</sub>O<sub>4</sub>. These results will provide a good theoretical basis for the recovery of Cu and Fe from the refractory oxide copper resource by the combined methods of sulfidation and flotation.</div></div>","PeriodicalId":7232,"journal":{"name":"Advanced Powder Technology","volume":"35 12","pages":"Article 104715"},"PeriodicalIF":4.2,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142656254","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-07DOI: 10.1016/j.apt.2024.104712
Shiv Shankar , Prakash D Chavan , Sujan Saha , Gajanan Sahu , Soubhik Kumar Bhaumik
Carbon capture at elevated temperatures (200-450°C) using MgO-based solid sorbents, typically suffers from slow kinetics and premature saturation lowering the overall uptake performance. A key factor responsible for this is the agglomeration of MgCO3 during carbonation, which could be potentially overcome by the addition of inert along with promoters. In this context, this work systematically investigates the infusion of Fly ash (FA) as inert in pure MgO and alkali-salt-promoted MgO-based sorbents prepared by the sol–gel method. The study includes characterizing the prepared sorbents based on morphological and textural properties and investigating the uptake kinetics along with cyclic performance based on thermogravimetric analysis under conditions of 250°C and 300°C for 45 mins. Among all tested modified sorbents, MgO_10NaNO3_5FA exhibited the highest uptake capacity of 14.56 mmol/g (MgO basis) followed by MgO_15NaNO3 (14.27 mmol/g) at 300°C. Cyclic studies over 10 cycles reveal higher conversion of FA-infused sorbent (MgO_10NaNO3_5FA: 59.76 %) over non-FA-infused sorbent (MgO_10NaNO3: 54.50 %) showing higher stability of the former. The results establish minimal FA infusion (5 %) in alkali nitrates promoted sorbent favorable for CO2 capture at moderate temperature while elucidating physicochemical aspects during uptake.
{"title":"Infusion of fly ash in alkali salt promoted MgO-based sorbent for CO2 capture at elevated temperatures","authors":"Shiv Shankar , Prakash D Chavan , Sujan Saha , Gajanan Sahu , Soubhik Kumar Bhaumik","doi":"10.1016/j.apt.2024.104712","DOIUrl":"10.1016/j.apt.2024.104712","url":null,"abstract":"<div><div>Carbon capture at elevated temperatures (200-450°C) using MgO-based solid sorbents, typically suffers from slow kinetics and premature saturation lowering the overall uptake performance. A key factor responsible for this is the agglomeration of MgCO<sub>3</sub> during carbonation, which could be potentially overcome by the addition of inert along with promoters. In this context, this work systematically investigates the infusion of Fly ash (FA) as inert in pure MgO and alkali-salt-promoted MgO-based sorbents prepared by the sol–gel method. The study includes characterizing the prepared sorbents based on morphological and textural properties and investigating the uptake kinetics along with cyclic performance based on thermogravimetric analysis under conditions of 250°C and 300°C for 45 mins. Among all tested modified sorbents, MgO_10NaNO<sub>3</sub>_5FA exhibited the highest uptake capacity of 14.56 mmol/g (MgO basis) followed by MgO_15NaNO<sub>3</sub> (14.27 mmol/g) at 300°C.<!--> <!-->Cyclic studies over 10 cycles reveal higher conversion of FA-infused sorbent (MgO_10NaNO<sub>3</sub>_5FA: 59.76 %) over non-FA-infused sorbent (MgO_10NaNO<sub>3</sub>: 54.50 %) showing higher stability of the former. The results establish minimal FA infusion (5 %) in alkali nitrates promoted sorbent favorable for CO<sub>2</sub> capture at moderate temperature while elucidating physicochemical aspects during uptake.</div></div>","PeriodicalId":7232,"journal":{"name":"Advanced Powder Technology","volume":"35 12","pages":"Article 104712"},"PeriodicalIF":4.2,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142656303","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-06DOI: 10.1016/j.apt.2024.104713
Denis Mutebi , Frantisek Miksik , Andrew M. Spring , Indri Yaningsih , Takahiko Miyazaki , Kyaw Thu
This research reports conventionally-synthesized-zeolites with comparatively large surface area (SSA) and water-uptake prepared solely from waste-pumice. Notably, the synthesis process avoided using additional commercial raw materials, organic templates, and high temperatures, so that the process was less costly and ecofriendly. To optimize the process, the synthesis time was varied, and the mixture of the raw material and alkaline solution was stirred for 12 h. The zeolite mother liquor was also recycled. Water adsorption experiments were carried out using gravimetric measurements. The Na-P1-rich zeolite product with an optimal water uptake of 0.256 g/g was synthesized after 48 h of hydrothermal activation (H). On the other hand, the product’s optimal SSA of 186 m2/g was achieved after 36H under similar conditions (rich in faujasite). Adsorption isotherms showed that water uptake increased with activation time and with the inclusion of mother liquor recycling. Furthermore, recycling resulted in a product with enhanced SSA compared to its precursor. Un-recycled products exhibited relatively high-water uptake both at low and high relative-pressure, while the recycled product had a high uptake at high relative pressure. All products could be used in adsorption heat pump (AHP) applications (air conditioning) suited for high relative humidity (RH) environments. However, high-synthesis-time non-recycled products could also work for low RH AHP applications.
{"title":"Optimization of conventional-zeolite-synthesis from waste pumice for water adsorption","authors":"Denis Mutebi , Frantisek Miksik , Andrew M. Spring , Indri Yaningsih , Takahiko Miyazaki , Kyaw Thu","doi":"10.1016/j.apt.2024.104713","DOIUrl":"10.1016/j.apt.2024.104713","url":null,"abstract":"<div><div>This research reports conventionally-synthesized-zeolites with comparatively large surface area (SSA) and water-uptake prepared solely from waste-pumice. Notably, the synthesis process avoided using additional commercial raw materials, organic templates, and high temperatures, so that the process was less costly and ecofriendly. To optimize the process, the synthesis time was varied, and the mixture of the raw material and alkaline solution was stirred for 12 h. The zeolite mother liquor was also recycled. Water adsorption experiments were carried out using gravimetric measurements. The Na-P1-rich zeolite product with an optimal water uptake of 0.256 g/g was synthesized after 48 h of hydrothermal activation (H). On the other hand, the product’s optimal SSA of 186 m<sup>2</sup>/g was achieved after 36H under similar conditions (rich in faujasite). Adsorption isotherms showed that water uptake increased with activation time and with the inclusion of mother liquor recycling. Furthermore, recycling resulted in a product with enhanced SSA compared to its precursor. Un-recycled products exhibited relatively high-water uptake both at low and high relative-pressure, while the recycled product had a high uptake at high relative pressure. All products could be used in adsorption heat pump (AHP) applications (air conditioning) suited for high relative humidity (RH) environments. However, high-synthesis-time non-recycled products could also work for low RH AHP applications.</div></div>","PeriodicalId":7232,"journal":{"name":"Advanced Powder Technology","volume":"35 12","pages":"Article 104713"},"PeriodicalIF":4.2,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142593192","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We found that the impact energy calculated by discrete element method (DEM) simulation can be used to explain the liberation of materials from electronic scrap (e-scrap) in a previous study; however, the absolute value of the impact energy had not been validated. Thus, we attempted to confirm the reliability by considering the particle velocity, which is highly related to impact energy. The comminution experiment was conducted using a drum-type agitation mill, and the particle velocity was measured by 3D particle tracking velocimetry (PTV) based on moving body analysis. The particle velocities for both the DEM simulation and PTV were compared for two types of particles, a non-breakable steel component and a connecting component that represents a breakable form of e-scrap. As a result, the particle velocities obtained from the two methods were within a relative error of 10% for the steel component, and thus the reliability of the impact energy was indirectly confirmed. In contrast, for the connecting component, the particle velocity from the DEM simulations was more than 50% higher, suggesting the influence of fracture energy. By calibrating the DEM simulation based on the particle velocity from PTV, the energy efficiency of fracture was estimated to be approximately 60%.
{"title":"Validation of DEM simulations for a drum-type agitation mill using particle velocities measured by 3D PTV","authors":"Takuya Tatsumoto , Yutaro Takaya , Yuki Tsunazawa , Taketoshi Koita , Keishi Oyama , Chiharu Tokoro","doi":"10.1016/j.apt.2024.104693","DOIUrl":"10.1016/j.apt.2024.104693","url":null,"abstract":"<div><div>We found that the impact energy calculated by discrete element method (DEM) simulation can be used to explain the liberation of materials from electronic scrap (e-scrap) in a previous study; however, the absolute value of the impact energy had not been validated. Thus, we attempted to confirm the reliability by considering the particle velocity, which is highly related to impact energy. The comminution experiment was conducted using a drum-type agitation mill, and the particle velocity was measured by 3D particle tracking velocimetry (PTV) based on moving body analysis. The particle velocities for both the DEM simulation and PTV were compared for two types of particles, a non-breakable steel component and a connecting component that represents a breakable form of e-scrap. As a result, the particle velocities obtained from the two methods were within a relative error of 10% for the steel component, and thus the reliability of the impact energy was indirectly confirmed. In contrast, for the connecting component, the particle velocity from the DEM simulations was more than 50% higher, suggesting the influence of fracture energy. By calibrating the DEM simulation based on the particle velocity from PTV, the energy efficiency of fracture was estimated to be approximately 60%.</div></div>","PeriodicalId":7232,"journal":{"name":"Advanced Powder Technology","volume":"35 12","pages":"Article 104693"},"PeriodicalIF":4.2,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142578388","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-31DOI: 10.1016/j.apt.2024.104702
A.R. Khoei , M. Vafaei Sefti , A. Rezaei Sameti
In this paper, the warm compaction process of alumina ceramic nano-powders is investigated through the molecular dynamics method, emphasizing the impact of nanoparticle size, heating temperature, and confining pressure on the final green product. The study unravels the complexities of the alumina compaction process with a focus on alpha-alumina (α-Al2O3) based on the reactive force field (ReaxFF). Three distinct stages are performed through the MD analysis of the warm compaction process, i.e. relaxing the nano-powders, increasing the pressure and temperature, and decreasing them to the room conditions. The nano-powders are generated with various sizes of nanoparticles to facilitate a comprehensive exploration of size effect on the compaction behavior. The accuracy of the proposed computational model is verified by comparing the results of the alumina nano-powder warm compaction process with those of experimental data. The optimal hold time is determined for the peak density in the MD analysis of the warm compaction process. The results highlight a nonlinear behavior of heating temperature and pressure on the relative density of the final green product, such that the temperature influence significantly reduces by increasing the pressure. Moreover, the size of nanoparticles is investigated during the warm compaction process of alumina nano-powders; it is shown that the relative density and energy density of the final green product increase by decreasing the size of nanoparticles.
{"title":"Reactive molecular dynamics analysis of alumina nano-powders under warm compaction process","authors":"A.R. Khoei , M. Vafaei Sefti , A. Rezaei Sameti","doi":"10.1016/j.apt.2024.104702","DOIUrl":"10.1016/j.apt.2024.104702","url":null,"abstract":"<div><div>In this paper, the warm compaction process of alumina ceramic nano-powders is investigated through the molecular dynamics method, emphasizing the impact of nanoparticle size, heating temperature, and confining pressure on the final green product. The study unravels the complexities of the alumina compaction process with a focus on alpha-alumina (α-Al<sub>2</sub>O<sub>3</sub>) based on the reactive force field (ReaxFF). Three distinct stages are performed through the MD analysis of the warm compaction process, i.e. relaxing the nano-powders, increasing the pressure and temperature, and decreasing them to the room conditions. The nano-powders are generated with various sizes of nanoparticles to facilitate a comprehensive exploration of size effect on the compaction behavior. The accuracy of the proposed computational model is verified by comparing the results of the alumina nano-powder warm compaction process with those of experimental data. The optimal hold time is determined for the peak density in the MD analysis of the warm compaction process. The results highlight a nonlinear behavior of heating temperature and pressure on the relative density of the final green product, such that the temperature influence significantly reduces by increasing the pressure. Moreover, the size of nanoparticles is investigated during the warm compaction process of alumina nano-powders; it is shown that the relative density and energy density of the final green product increase by decreasing the size of nanoparticles.</div></div>","PeriodicalId":7232,"journal":{"name":"Advanced Powder Technology","volume":"35 12","pages":"Article 104702"},"PeriodicalIF":4.2,"publicationDate":"2024-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142555029","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In order to dissipate heat in electronic devices, particle-dispersed resins are commonly used to fill gaps between components. It is crucial to reduce the viscosity of the particle-dispersed resin to ensure complete filling. To achieve low viscosity, surface-modified particles using silane coupling agents have been developed to enhance compatibility with the resin. In this study, we focused on the Hansen solubility parameter (HSP) indicating compatibility of substances. We established a method to accurately predict HSP values using a combination of quantum chemical calculations and machine learning techniques known as the quantitative structure property relationships method (QSPR-method). Using this method, we calculated the HSP values of various silane coupling agents for modifying alumina particles and investigated their correlation with the viscosity of the alumina particle-dispersed resin. This study aimed to verify whether the QSPR method can be used to design silane coupling agents that can significantly reduce viscosity of particle-dispersed resins.
{"title":"Viscosity control of alumina dispersed resin through design of surface modifier by a QSPR-method","authors":"Ryosuke Maekawa , Haruna Nakayoshi , Makoto Kawano , Chika Takai","doi":"10.1016/j.apt.2024.104701","DOIUrl":"10.1016/j.apt.2024.104701","url":null,"abstract":"<div><div>In order to dissipate heat in electronic devices, particle-dispersed resins are commonly used to fill gaps between components. It is crucial to reduce the viscosity of the particle-dispersed resin to ensure complete filling. To achieve low viscosity, surface-modified particles using silane coupling agents have been developed to enhance compatibility with the resin. In this study, we focused on the Hansen solubility parameter (HSP) indicating compatibility of substances. We established a method to accurately predict HSP values using a combination of quantum chemical calculations and machine learning techniques known as the quantitative structure property relationships method (QSPR-method). Using this method, we calculated the HSP values of various silane coupling agents for modifying alumina particles and investigated their correlation with the viscosity of the alumina particle-dispersed resin. This study aimed to verify whether the QSPR method can be used to design silane coupling agents that can significantly reduce viscosity of particle-dispersed resins.</div></div>","PeriodicalId":7232,"journal":{"name":"Advanced Powder Technology","volume":"35 12","pages":"Article 104701"},"PeriodicalIF":4.2,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142554492","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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